797 lines
26 KiB
C
797 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <errno.h>
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#include <string.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include <../../../tools/include/linux/filter.h>
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int vals[] SEC(".data.vals") = {1, 2, 3, 4};
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__naked __noinline __used
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static unsigned long identity_subprog()
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{
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/* the simplest *static* 64-bit identity function */
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asm volatile (
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"r0 = r1;"
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"exit;"
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);
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}
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__noinline __used
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unsigned long global_identity_subprog(__u64 x)
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{
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/* the simplest *global* 64-bit identity function */
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return x;
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}
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__naked __noinline __used
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static unsigned long callback_subprog()
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{
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/* the simplest callback function */
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asm volatile (
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"r0 = 0;"
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"exit;"
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("7: (0f) r1 += r0")
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__msg("mark_precise: frame0: regs=r0 stack= before 6: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r0 stack= before 5: (27) r0 *= 4")
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__msg("mark_precise: frame0: regs=r0 stack= before 11: (95) exit")
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__msg("mark_precise: frame1: regs=r0 stack= before 10: (bf) r0 = r1")
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__msg("mark_precise: frame1: regs=r1 stack= before 4: (85) call pc+5")
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__msg("mark_precise: frame0: regs=r1 stack= before 3: (bf) r1 = r6")
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__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 3")
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__naked int subprog_result_precise(void)
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{
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asm volatile (
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"r6 = 3;"
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/* pass r6 through r1 into subprog to get it back as r0;
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* this whole chain will have to be marked as precise later
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*/
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"r1 = r6;"
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"call identity_subprog;"
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/* now use subprog's returned value (which is a
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* r6 -> r1 -> r0 chain), as index into vals array, forcing
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* all of that to be known precisely
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*/
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"r0 *= 4;"
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"r1 = %[vals];"
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/* here r0->r1->r6 chain is forced to be precise and has to be
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* propagated back to the beginning, including through the
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* subprog call
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*/
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"r1 += r0;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals)
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: __clobber_common, "r6"
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);
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}
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__naked __noinline __used
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static unsigned long fp_leaking_subprog()
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{
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asm volatile (
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".8byte %[r0_eq_r10_cast_s8];"
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"exit;"
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:: __imm_insn(r0_eq_r10_cast_s8, BPF_MOVSX64_REG(BPF_REG_0, BPF_REG_10, 8))
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);
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}
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__naked __noinline __used
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static unsigned long sneaky_fp_leaking_subprog()
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{
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asm volatile (
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"r1 = r10;"
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".8byte %[r0_eq_r1_cast_s8];"
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"exit;"
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:: __imm_insn(r0_eq_r1_cast_s8, BPF_MOVSX64_REG(BPF_REG_0, BPF_REG_1, 8))
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("6: (0f) r1 += r0")
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__msg("mark_precise: frame0: last_idx 6 first_idx 0 subseq_idx -1")
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__msg("mark_precise: frame0: regs=r0 stack= before 5: (bf) r1 = r6")
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__msg("mark_precise: frame0: regs=r0 stack= before 4: (27) r0 *= 4")
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__msg("mark_precise: frame0: regs=r0 stack= before 3: (57) r0 &= 3")
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__msg("mark_precise: frame0: regs=r0 stack= before 10: (95) exit")
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__msg("mark_precise: frame1: regs=r0 stack= before 9: (bf) r0 = (s8)r10")
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__msg("7: R0_w=scalar")
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__naked int fp_precise_subprog_result(void)
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{
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asm volatile (
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"call fp_leaking_subprog;"
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/* use subprog's returned value (which is derived from r10=fp
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* register), as index into vals array, forcing all of that to
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* be known precisely
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*/
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"r0 &= 3;"
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"r0 *= 4;"
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"r1 = %[vals];"
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/* force precision marking */
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"r1 += r0;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals)
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: __clobber_common
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("6: (0f) r1 += r0")
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__msg("mark_precise: frame0: last_idx 6 first_idx 0 subseq_idx -1")
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__msg("mark_precise: frame0: regs=r0 stack= before 5: (bf) r1 = r6")
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__msg("mark_precise: frame0: regs=r0 stack= before 4: (27) r0 *= 4")
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__msg("mark_precise: frame0: regs=r0 stack= before 3: (57) r0 &= 3")
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__msg("mark_precise: frame0: regs=r0 stack= before 11: (95) exit")
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__msg("mark_precise: frame1: regs=r0 stack= before 10: (bf) r0 = (s8)r1")
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/* here r1 is marked precise, even though it's fp register, but that's fine
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* because by the time we get out of subprogram it has to be derived from r10
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* anyways, at which point we'll break precision chain
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*/
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__msg("mark_precise: frame1: regs=r1 stack= before 9: (bf) r1 = r10")
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__msg("7: R0_w=scalar")
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__naked int sneaky_fp_precise_subprog_result(void)
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{
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asm volatile (
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"call sneaky_fp_leaking_subprog;"
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/* use subprog's returned value (which is derived from r10=fp
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* register), as index into vals array, forcing all of that to
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* be known precisely
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*/
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"r0 &= 3;"
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"r0 *= 4;"
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"r1 = %[vals];"
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/* force precision marking */
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"r1 += r0;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals)
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: __clobber_common
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("9: (0f) r1 += r0")
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__msg("mark_precise: frame0: last_idx 9 first_idx 0")
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__msg("mark_precise: frame0: regs=r0 stack= before 8: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r0 stack= before 7: (27) r0 *= 4")
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__msg("mark_precise: frame0: regs=r0 stack= before 5: (a5) if r0 < 0x4 goto pc+1")
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__msg("mark_precise: frame0: regs=r0 stack= before 4: (85) call pc+7")
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__naked int global_subprog_result_precise(void)
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{
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asm volatile (
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"r6 = 3;"
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/* pass r6 through r1 into subprog to get it back as r0;
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* given global_identity_subprog is global, precision won't
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* propagate all the way back to r6
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*/
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"r1 = r6;"
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"call global_identity_subprog;"
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/* now use subprog's returned value (which is unknown now, so
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* we need to clamp it), as index into vals array, forcing r0
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* to be marked precise (with no effect on r6, though)
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*/
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"if r0 < %[vals_arr_sz] goto 1f;"
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"r0 = %[vals_arr_sz] - 1;"
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"1:"
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"r0 *= 4;"
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"r1 = %[vals];"
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/* here r0 is forced to be precise and has to be
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* propagated back to the global subprog call, but it
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* shouldn't go all the way to mark r6 as precise
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*/
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"r1 += r0;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals),
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__imm_const(vals_arr_sz, ARRAY_SIZE(vals))
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: __clobber_common, "r6"
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);
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}
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__naked __noinline __used
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static unsigned long loop_callback_bad()
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{
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/* bpf_loop() callback that can return values outside of [0, 1] range */
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asm volatile (
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"call %[bpf_get_prandom_u32];"
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"if r0 s> 1000 goto 1f;"
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"r0 = 0;"
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"1:"
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"goto +0;" /* checkpoint */
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/* bpf_loop() expects [0, 1] values, so branch above skipping
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* r0 = 0; should lead to a failure, but if exit instruction
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* doesn't enforce r0's precision, this callback will be
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* successfully verified
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*/
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"exit;"
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:
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: __imm(bpf_get_prandom_u32)
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: __clobber_common
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);
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}
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SEC("?raw_tp")
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__failure __log_level(2)
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__flag(BPF_F_TEST_STATE_FREQ)
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/* check that fallthrough code path marks r0 as precise */
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__msg("mark_precise: frame1: regs=r0 stack= before 11: (b7) r0 = 0")
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/* check that we have branch code path doing its own validation */
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__msg("from 10 to 12: frame1: R0=scalar(smin=umin=1001")
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/* check that branch code path marks r0 as precise, before failing */
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__msg("mark_precise: frame1: regs=r0 stack= before 9: (85) call bpf_get_prandom_u32#7")
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__msg("At callback return the register R0 has smin=1001 should have been in [0, 1]")
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__naked int callback_precise_return_fail(void)
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{
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asm volatile (
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"r1 = 1;" /* nr_loops */
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"r2 = %[loop_callback_bad];" /* callback_fn */
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"r3 = 0;" /* callback_ctx */
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"r4 = 0;" /* flags */
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"call %[bpf_loop];"
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"r0 = 0;"
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"exit;"
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:
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: __imm_ptr(loop_callback_bad),
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__imm(bpf_loop)
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: __clobber_common
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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/* First simulated path does not include callback body,
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* r1 and r4 are always precise for bpf_loop() calls.
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*/
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__msg("9: (85) call bpf_loop#181")
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__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
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__msg("mark_precise: frame0: parent state regs=r4 stack=:")
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__msg("mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx 9")
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__msg("mark_precise: frame0: regs=r4 stack= before 8: (b7) r4 = 0")
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__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
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__msg("mark_precise: frame0: parent state regs=r1 stack=:")
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__msg("mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx 9")
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__msg("mark_precise: frame0: regs=r1 stack= before 8: (b7) r4 = 0")
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__msg("mark_precise: frame0: regs=r1 stack= before 7: (b7) r3 = 0")
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__msg("mark_precise: frame0: regs=r1 stack= before 6: (bf) r2 = r8")
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__msg("mark_precise: frame0: regs=r1 stack= before 5: (bf) r1 = r6")
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__msg("mark_precise: frame0: regs=r6 stack= before 4: (b7) r6 = 3")
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/* r6 precision propagation */
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__msg("14: (0f) r1 += r6")
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__msg("mark_precise: frame0: last_idx 14 first_idx 9")
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__msg("mark_precise: frame0: regs=r6 stack= before 13: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r6 stack= before 12: (27) r6 *= 4")
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__msg("mark_precise: frame0: regs=r6 stack= before 11: (25) if r6 > 0x3 goto pc+4")
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__msg("mark_precise: frame0: regs=r0,r6 stack= before 10: (bf) r6 = r0")
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__msg("mark_precise: frame0: regs=r0 stack= before 9: (85) call bpf_loop")
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/* State entering callback body popped from states stack */
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__msg("from 9 to 17: frame1:")
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__msg("17: frame1: R1=scalar() R2=0 R10=fp0 cb")
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__msg("17: (b7) r0 = 0")
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__msg("18: (95) exit")
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__msg("returning from callee:")
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__msg("to caller at 9:")
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__msg("frame 0: propagating r1,r4")
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__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
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__msg("mark_precise: frame0: regs=r1,r4 stack= before 18: (95) exit")
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__msg("from 18 to 9: safe")
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__naked int callback_result_precise(void)
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{
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asm volatile (
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"r6 = 3;"
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/* call subprog and use result; r0 shouldn't propagate back to
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* callback_subprog
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*/
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"r1 = r6;" /* nr_loops */
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"r2 = %[callback_subprog];" /* callback_fn */
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"r3 = 0;" /* callback_ctx */
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"r4 = 0;" /* flags */
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"call %[bpf_loop];"
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"r6 = r0;"
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"if r6 > 3 goto 1f;"
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"r6 *= 4;"
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"r1 = %[vals];"
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/* here r6 is forced to be precise and has to be propagated
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* back to the bpf_loop() call, but not beyond
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*/
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"r1 += r6;"
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"r0 = *(u32 *)(r1 + 0);"
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"1:"
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"exit;"
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:
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: __imm_ptr(vals),
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__imm_ptr(callback_subprog),
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__imm(bpf_loop)
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: __clobber_common, "r6"
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("7: (0f) r1 += r6")
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__msg("mark_precise: frame0: last_idx 7 first_idx 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 6: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r6 stack= before 5: (27) r6 *= 4")
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__msg("mark_precise: frame0: regs=r6 stack= before 11: (95) exit")
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__msg("mark_precise: frame1: regs= stack= before 10: (bf) r0 = r1")
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__msg("mark_precise: frame1: regs= stack= before 4: (85) call pc+5")
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__msg("mark_precise: frame0: regs=r6 stack= before 3: (b7) r1 = 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 3")
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__naked int parent_callee_saved_reg_precise(void)
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{
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asm volatile (
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"r6 = 3;"
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/* call subprog and ignore result; we need this call only to
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* complicate jump history
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*/
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"r1 = 0;"
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"call identity_subprog;"
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"r6 *= 4;"
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"r1 = %[vals];"
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/* here r6 is forced to be precise and has to be propagated
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* back to the beginning, handling (and ignoring) subprog call
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*/
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"r1 += r6;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals)
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: __clobber_common, "r6"
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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__msg("7: (0f) r1 += r6")
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__msg("mark_precise: frame0: last_idx 7 first_idx 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 6: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r6 stack= before 5: (27) r6 *= 4")
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__msg("mark_precise: frame0: regs=r6 stack= before 4: (85) call pc+5")
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__msg("mark_precise: frame0: regs=r6 stack= before 3: (b7) r1 = 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 3")
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__naked int parent_callee_saved_reg_precise_global(void)
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{
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asm volatile (
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"r6 = 3;"
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/* call subprog and ignore result; we need this call only to
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* complicate jump history
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*/
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"r1 = 0;"
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"call global_identity_subprog;"
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"r6 *= 4;"
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"r1 = %[vals];"
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/* here r6 is forced to be precise and has to be propagated
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* back to the beginning, handling (and ignoring) subprog call
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*/
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"r1 += r6;"
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"r0 = *(u32 *)(r1 + 0);"
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"exit;"
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:
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: __imm_ptr(vals)
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: __clobber_common, "r6"
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);
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}
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SEC("?raw_tp")
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__success __log_level(2)
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/* First simulated path does not include callback body */
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__msg("12: (0f) r1 += r6")
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__msg("mark_precise: frame0: last_idx 12 first_idx 9")
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__msg("mark_precise: frame0: regs=r6 stack= before 11: (bf) r1 = r7")
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__msg("mark_precise: frame0: regs=r6 stack= before 10: (27) r6 *= 4")
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__msg("mark_precise: frame0: regs=r6 stack= before 9: (85) call bpf_loop")
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__msg("mark_precise: frame0: parent state regs=r6 stack=:")
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__msg("mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx 9")
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__msg("mark_precise: frame0: regs=r6 stack= before 8: (b7) r4 = 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 7: (b7) r3 = 0")
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__msg("mark_precise: frame0: regs=r6 stack= before 6: (bf) r2 = r8")
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__msg("mark_precise: frame0: regs=r6 stack= before 5: (b7) r1 = 1")
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__msg("mark_precise: frame0: regs=r6 stack= before 4: (b7) r6 = 3")
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/* State entering callback body popped from states stack */
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__msg("from 9 to 15: frame1:")
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__msg("15: frame1: R1=scalar() R2=0 R10=fp0 cb")
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__msg("15: (b7) r0 = 0")
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__msg("16: (95) exit")
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__msg("returning from callee:")
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__msg("to caller at 9:")
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/* r1, r4 are always precise for bpf_loop(),
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* r6 was marked before backtracking to callback body.
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*/
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__msg("frame 0: propagating r1,r4,r6")
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__msg("mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1")
|
|
__msg("mark_precise: frame0: regs=r1,r4,r6 stack= before 16: (95) exit")
|
|
__msg("mark_precise: frame1: regs= stack= before 15: (b7) r0 = 0")
|
|
__msg("mark_precise: frame1: regs= stack= before 9: (85) call bpf_loop")
|
|
__msg("mark_precise: frame0: parent state regs= stack=:")
|
|
__msg("from 16 to 9: safe")
|
|
__naked int parent_callee_saved_reg_precise_with_callback(void)
|
|
{
|
|
asm volatile (
|
|
"r6 = 3;"
|
|
|
|
/* call subprog and ignore result; we need this call only to
|
|
* complicate jump history
|
|
*/
|
|
"r1 = 1;" /* nr_loops */
|
|
"r2 = %[callback_subprog];" /* callback_fn */
|
|
"r3 = 0;" /* callback_ctx */
|
|
"r4 = 0;" /* flags */
|
|
"call %[bpf_loop];"
|
|
|
|
"r6 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r6 is forced to be precise and has to be propagated
|
|
* back to the beginning, handling (and ignoring) callback call
|
|
*/
|
|
"r1 += r6;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals),
|
|
__imm_ptr(callback_subprog),
|
|
__imm(bpf_loop)
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
__msg("9: (0f) r1 += r6")
|
|
__msg("mark_precise: frame0: last_idx 9 first_idx 6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 8: (bf) r1 = r7")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 7: (27) r6 *= 4")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 6: (79) r6 = *(u64 *)(r10 -8)")
|
|
__msg("mark_precise: frame0: parent state regs= stack=-8:")
|
|
__msg("mark_precise: frame0: last_idx 13 first_idx 0")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 13: (95) exit")
|
|
__msg("mark_precise: frame1: regs= stack= before 12: (bf) r0 = r1")
|
|
__msg("mark_precise: frame1: regs= stack= before 5: (85) call pc+6")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 4: (b7) r1 = 0")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 3: (7b) *(u64 *)(r10 -8) = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 3")
|
|
__naked int parent_stack_slot_precise(void)
|
|
{
|
|
asm volatile (
|
|
/* spill reg */
|
|
"r6 = 3;"
|
|
"*(u64 *)(r10 - 8) = r6;"
|
|
|
|
/* call subprog and ignore result; we need this call only to
|
|
* complicate jump history
|
|
*/
|
|
"r1 = 0;"
|
|
"call identity_subprog;"
|
|
|
|
/* restore reg from stack; in this case we'll be carrying
|
|
* stack mask when going back into subprog through jump
|
|
* history
|
|
*/
|
|
"r6 = *(u64 *)(r10 - 8);"
|
|
|
|
"r6 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r6 is forced to be precise and has to be propagated
|
|
* back to the beginning, handling (and ignoring) subprog call
|
|
*/
|
|
"r1 += r6;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals)
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
__msg("9: (0f) r1 += r6")
|
|
__msg("mark_precise: frame0: last_idx 9 first_idx 0")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 8: (bf) r1 = r7")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 7: (27) r6 *= 4")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 6: (79) r6 = *(u64 *)(r10 -8)")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 5: (85) call pc+6")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 4: (b7) r1 = 0")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 3: (7b) *(u64 *)(r10 -8) = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 3")
|
|
__naked int parent_stack_slot_precise_global(void)
|
|
{
|
|
asm volatile (
|
|
/* spill reg */
|
|
"r6 = 3;"
|
|
"*(u64 *)(r10 - 8) = r6;"
|
|
|
|
/* call subprog and ignore result; we need this call only to
|
|
* complicate jump history
|
|
*/
|
|
"r1 = 0;"
|
|
"call global_identity_subprog;"
|
|
|
|
/* restore reg from stack; in this case we'll be carrying
|
|
* stack mask when going back into subprog through jump
|
|
* history
|
|
*/
|
|
"r6 = *(u64 *)(r10 - 8);"
|
|
|
|
"r6 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r6 is forced to be precise and has to be propagated
|
|
* back to the beginning, handling (and ignoring) subprog call
|
|
*/
|
|
"r1 += r6;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals)
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
/* First simulated path does not include callback body */
|
|
__msg("14: (0f) r1 += r6")
|
|
__msg("mark_precise: frame0: last_idx 14 first_idx 10")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 13: (bf) r1 = r7")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 12: (27) r6 *= 4")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 11: (79) r6 = *(u64 *)(r10 -8)")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 10: (85) call bpf_loop")
|
|
__msg("mark_precise: frame0: parent state regs= stack=-8:")
|
|
__msg("mark_precise: frame0: last_idx 9 first_idx 0 subseq_idx 10")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 9: (b7) r4 = 0")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 8: (b7) r3 = 0")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 7: (bf) r2 = r8")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 6: (bf) r1 = r6")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 5: (7b) *(u64 *)(r10 -8) = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 4: (b7) r6 = 3")
|
|
/* State entering callback body popped from states stack */
|
|
__msg("from 10 to 17: frame1:")
|
|
__msg("17: frame1: R1=scalar() R2=0 R10=fp0 cb")
|
|
__msg("17: (b7) r0 = 0")
|
|
__msg("18: (95) exit")
|
|
__msg("returning from callee:")
|
|
__msg("to caller at 10:")
|
|
/* r1, r4 are always precise for bpf_loop(),
|
|
* fp-8 was marked before backtracking to callback body.
|
|
*/
|
|
__msg("frame 0: propagating r1,r4,fp-8")
|
|
__msg("mark_precise: frame0: last_idx 10 first_idx 10 subseq_idx -1")
|
|
__msg("mark_precise: frame0: regs=r1,r4 stack=-8 before 18: (95) exit")
|
|
__msg("mark_precise: frame1: regs= stack= before 17: (b7) r0 = 0")
|
|
__msg("mark_precise: frame1: regs= stack= before 10: (85) call bpf_loop#181")
|
|
__msg("mark_precise: frame0: parent state regs= stack=:")
|
|
__msg("from 18 to 10: safe")
|
|
__naked int parent_stack_slot_precise_with_callback(void)
|
|
{
|
|
asm volatile (
|
|
/* spill reg */
|
|
"r6 = 3;"
|
|
"*(u64 *)(r10 - 8) = r6;"
|
|
|
|
/* ensure we have callback frame in jump history */
|
|
"r1 = r6;" /* nr_loops */
|
|
"r2 = %[callback_subprog];" /* callback_fn */
|
|
"r3 = 0;" /* callback_ctx */
|
|
"r4 = 0;" /* flags */
|
|
"call %[bpf_loop];"
|
|
|
|
/* restore reg from stack; in this case we'll be carrying
|
|
* stack mask when going back into subprog through jump
|
|
* history
|
|
*/
|
|
"r6 = *(u64 *)(r10 - 8);"
|
|
|
|
"r6 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r6 is forced to be precise and has to be propagated
|
|
* back to the beginning, handling (and ignoring) subprog call
|
|
*/
|
|
"r1 += r6;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals),
|
|
__imm_ptr(callback_subprog),
|
|
__imm(bpf_loop)
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
__noinline __used
|
|
static __u64 subprog_with_precise_arg(__u64 x)
|
|
{
|
|
return vals[x]; /* x is forced to be precise */
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
__msg("8: (0f) r2 += r1")
|
|
__msg("mark_precise: frame1: last_idx 8 first_idx 0")
|
|
__msg("mark_precise: frame1: regs=r1 stack= before 6: (18) r2 = ")
|
|
__msg("mark_precise: frame1: regs=r1 stack= before 5: (67) r1 <<= 2")
|
|
__msg("mark_precise: frame1: regs=r1 stack= before 2: (85) call pc+2")
|
|
__msg("mark_precise: frame0: regs=r1 stack= before 1: (bf) r1 = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 0: (b7) r6 = 3")
|
|
__naked int subprog_arg_precise(void)
|
|
{
|
|
asm volatile (
|
|
"r6 = 3;"
|
|
"r1 = r6;"
|
|
/* subprog_with_precise_arg expects its argument to be
|
|
* precise, so r1->r6 will be marked precise from inside the
|
|
* subprog
|
|
*/
|
|
"call subprog_with_precise_arg;"
|
|
"r0 += r6;"
|
|
"exit;"
|
|
:
|
|
:
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
/* r1 is pointer to stack slot;
|
|
* r2 is a register to spill into that slot
|
|
* subprog also spills r2 into its own stack slot
|
|
*/
|
|
__naked __noinline __used
|
|
static __u64 subprog_spill_reg_precise(void)
|
|
{
|
|
asm volatile (
|
|
/* spill to parent stack */
|
|
"*(u64 *)(r1 + 0) = r2;"
|
|
/* spill to subprog stack (we use -16 offset to avoid
|
|
* accidental confusion with parent's -8 stack slot in
|
|
* verifier log output)
|
|
*/
|
|
"*(u64 *)(r10 - 16) = r2;"
|
|
/* use both spills as return result to propagete precision everywhere */
|
|
"r0 = *(u64 *)(r10 - 16);"
|
|
"r2 = *(u64 *)(r1 + 0);"
|
|
"r0 += r2;"
|
|
"exit;"
|
|
);
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
__msg("10: (0f) r1 += r7")
|
|
__msg("mark_precise: frame0: last_idx 10 first_idx 7 subseq_idx -1")
|
|
__msg("mark_precise: frame0: regs=r7 stack= before 9: (bf) r1 = r8")
|
|
__msg("mark_precise: frame0: regs=r7 stack= before 8: (27) r7 *= 4")
|
|
__msg("mark_precise: frame0: regs=r7 stack= before 7: (79) r7 = *(u64 *)(r10 -8)")
|
|
__msg("mark_precise: frame0: parent state regs= stack=-8: R0_w=2 R6_w=1 R8_rw=map_value(map=.data.vals,ks=4,vs=16) R10=fp0 fp-8_rw=P1")
|
|
__msg("mark_precise: frame0: last_idx 18 first_idx 0 subseq_idx 7")
|
|
__msg("mark_precise: frame0: regs= stack=-8 before 18: (95) exit")
|
|
__msg("mark_precise: frame1: regs= stack= before 17: (0f) r0 += r2")
|
|
__msg("mark_precise: frame1: regs= stack= before 16: (79) r2 = *(u64 *)(r1 +0)")
|
|
__msg("mark_precise: frame1: regs= stack= before 15: (79) r0 = *(u64 *)(r10 -16)")
|
|
__msg("mark_precise: frame1: regs= stack= before 14: (7b) *(u64 *)(r10 -16) = r2")
|
|
__msg("mark_precise: frame1: regs= stack= before 13: (7b) *(u64 *)(r1 +0) = r2")
|
|
__msg("mark_precise: frame1: regs=r2 stack= before 6: (85) call pc+6")
|
|
__msg("mark_precise: frame0: regs=r2 stack= before 5: (bf) r2 = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 4: (07) r1 += -8")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 3: (bf) r1 = r10")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 1")
|
|
__naked int subprog_spill_into_parent_stack_slot_precise(void)
|
|
{
|
|
asm volatile (
|
|
"r6 = 1;"
|
|
|
|
/* pass pointer to stack slot and r6 to subprog;
|
|
* r6 will be marked precise and spilled into fp-8 slot, which
|
|
* also should be marked precise
|
|
*/
|
|
"r1 = r10;"
|
|
"r1 += -8;"
|
|
"r2 = r6;"
|
|
"call subprog_spill_reg_precise;"
|
|
|
|
/* restore reg from stack; in this case we'll be carrying
|
|
* stack mask when going back into subprog through jump
|
|
* history
|
|
*/
|
|
"r7 = *(u64 *)(r10 - 8);"
|
|
|
|
"r7 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r7 is forced to be precise and has to be propagated
|
|
* back to the beginning, handling subprog call and logic
|
|
*/
|
|
"r1 += r7;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals)
|
|
: __clobber_common, "r6", "r7"
|
|
);
|
|
}
|
|
|
|
SEC("?raw_tp")
|
|
__success __log_level(2)
|
|
__msg("17: (0f) r1 += r0")
|
|
__msg("mark_precise: frame0: last_idx 17 first_idx 0 subseq_idx -1")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 16: (bf) r1 = r7")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 15: (27) r0 *= 4")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 14: (79) r0 = *(u64 *)(r10 -16)")
|
|
__msg("mark_precise: frame0: regs= stack=-16 before 13: (7b) *(u64 *)(r7 -8) = r0")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 12: (79) r0 = *(u64 *)(r8 +16)")
|
|
__msg("mark_precise: frame0: regs= stack=-16 before 11: (7b) *(u64 *)(r8 +16) = r0")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 10: (79) r0 = *(u64 *)(r7 -8)")
|
|
__msg("mark_precise: frame0: regs= stack=-16 before 9: (7b) *(u64 *)(r10 -16) = r0")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 8: (07) r8 += -32")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 7: (bf) r8 = r10")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 6: (07) r7 += -8")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 5: (bf) r7 = r10")
|
|
__msg("mark_precise: frame0: regs=r0 stack= before 21: (95) exit")
|
|
__msg("mark_precise: frame1: regs=r0 stack= before 20: (bf) r0 = r1")
|
|
__msg("mark_precise: frame1: regs=r1 stack= before 4: (85) call pc+15")
|
|
__msg("mark_precise: frame0: regs=r1 stack= before 3: (bf) r1 = r6")
|
|
__msg("mark_precise: frame0: regs=r6 stack= before 2: (b7) r6 = 1")
|
|
__naked int stack_slot_aliases_precision(void)
|
|
{
|
|
asm volatile (
|
|
"r6 = 1;"
|
|
/* pass r6 through r1 into subprog to get it back as r0;
|
|
* this whole chain will have to be marked as precise later
|
|
*/
|
|
"r1 = r6;"
|
|
"call identity_subprog;"
|
|
/* let's setup two registers that are aliased to r10 */
|
|
"r7 = r10;"
|
|
"r7 += -8;" /* r7 = r10 - 8 */
|
|
"r8 = r10;"
|
|
"r8 += -32;" /* r8 = r10 - 32 */
|
|
/* now spill subprog's return value (a r6 -> r1 -> r0 chain)
|
|
* a few times through different stack pointer regs, making
|
|
* sure to use r10, r7, and r8 both in LDX and STX insns, and
|
|
* *importantly* also using a combination of const var_off and
|
|
* insn->off to validate that we record final stack slot
|
|
* correctly, instead of relying on just insn->off derivation,
|
|
* which is only valid for r10-based stack offset
|
|
*/
|
|
"*(u64 *)(r10 - 16) = r0;"
|
|
"r0 = *(u64 *)(r7 - 8);" /* r7 - 8 == r10 - 16 */
|
|
"*(u64 *)(r8 + 16) = r0;" /* r8 + 16 = r10 - 16 */
|
|
"r0 = *(u64 *)(r8 + 16);"
|
|
"*(u64 *)(r7 - 8) = r0;"
|
|
"r0 = *(u64 *)(r10 - 16);"
|
|
/* get ready to use r0 as an index into array to force precision */
|
|
"r0 *= 4;"
|
|
"r1 = %[vals];"
|
|
/* here r0->r1->r6 chain is forced to be precise and has to be
|
|
* propagated back to the beginning, including through the
|
|
* subprog call and all the stack spills and loads
|
|
*/
|
|
"r1 += r0;"
|
|
"r0 = *(u32 *)(r1 + 0);"
|
|
"exit;"
|
|
:
|
|
: __imm_ptr(vals)
|
|
: __clobber_common, "r6"
|
|
);
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|