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Merge branch 'fix-accessing-first-syscall-argument-on-rv64'

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Pu Lehui says:

====================
Fix accessing first syscall argument on RV64

On RV64, as Ilya mentioned before [0], the first syscall parameter should be
accessed through orig_a0 (see arch/riscv64/include/asm/syscall.h),
otherwise it will cause selftests like bpf_syscall_macro, vmlinux,
test_lsm, etc. to fail on RV64.

Link: https://lore.kernel.org/bpf/20220209021745.2215452-1-iii@linux.ibm.com [0]

v3:
- Fix test case error.

v2: https://lore.kernel.org/all/20240831023646.1558629-1-pulehui@huaweicloud.com/
- Access first syscall argument with CO-RE direct read. (Andrii)

v1: https://lore.kernel.org/all/20240829133453.882259-1-pulehui@huaweicloud.com/
====================

Link: https://lore.kernel.org/r/20240831041934.1629216-1-pulehui@huaweicloud.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Andrii Nakryiko 2024-09-04 17:03:52 -07:00
commit aa01d13eec
3 changed files with 12 additions and 11 deletions
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17
tools/lib/bpf/bpf_tracing.h
View File

@ -163,7 +163,7 @@
struct pt_regs___s390 {
unsigned long orig_gpr2;
};
} __attribute__((preserve_access_index));
/* s390 provides user_pt_regs instead of struct pt_regs to userspace */
#define __PT_REGS_CAST(x) ((const user_pt_regs *)(x))
@ -179,7 +179,7 @@ struct pt_regs___s390 {
#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
#define __PT_PARM6_SYSCALL_REG gprs[7]
#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1_CORE_SYSCALL(x)
#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___s390 *)(x))->__PT_PARM1_SYSCALL_REG)
#define PT_REGS_PARM1_CORE_SYSCALL(x) \
BPF_CORE_READ((const struct pt_regs___s390 *)(x), __PT_PARM1_SYSCALL_REG)
@ -222,7 +222,7 @@ struct pt_regs___s390 {
struct pt_regs___arm64 {
unsigned long orig_x0;
};
} __attribute__((preserve_access_index));
/* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
#define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
@ -241,7 +241,7 @@ struct pt_regs___arm64 {
#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1_CORE_SYSCALL(x)
#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___arm64 *)(x))->__PT_PARM1_SYSCALL_REG)
#define PT_REGS_PARM1_CORE_SYSCALL(x) \
BPF_CORE_READ((const struct pt_regs___arm64 *)(x), __PT_PARM1_SYSCALL_REG)
@ -351,6 +351,10 @@ struct pt_regs___arm64 {
* https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#risc-v-calling-conventions
*/
struct pt_regs___riscv {
unsigned long orig_a0;
} __attribute__((preserve_access_index));
/* riscv provides struct user_regs_struct instead of struct pt_regs to userspace */
#define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
#define __PT_PARM1_REG a0
@ -362,12 +366,15 @@ struct pt_regs___arm64 {
#define __PT_PARM7_REG a6
#define __PT_PARM8_REG a7
#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
#define __PT_PARM1_SYSCALL_REG orig_a0
#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___riscv *)(x))->__PT_PARM1_SYSCALL_REG)
#define PT_REGS_PARM1_CORE_SYSCALL(x) \
BPF_CORE_READ((const struct pt_regs___riscv *)(x), __PT_PARM1_SYSCALL_REG)
#define __PT_RET_REG ra
#define __PT_FP_REG s0

4
tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
View File

@ -38,11 +38,7 @@ void test_bpf_syscall_macro(void)
/* check whether args of syscall are copied correctly */
prctl(exp_arg1, exp_arg2, exp_arg3, exp_arg4, exp_arg5);
#if defined(__aarch64__) || defined(__s390__)
ASSERT_NEQ(skel->bss->arg1, exp_arg1, "syscall_arg1");
#else
ASSERT_EQ(skel->bss->arg1, exp_arg1, "syscall_arg1");
#endif
ASSERT_EQ(skel->bss->arg2, exp_arg2, "syscall_arg2");
ASSERT_EQ(skel->bss->arg3, exp_arg3, "syscall_arg3");
/* it cannot copy arg4 when uses PT_REGS_PARM4 on x86_64 */

2
tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
View File

@ -43,9 +43,7 @@ int BPF_KPROBE(handle_sys_prctl)
/* test for PT_REGS_PARM */
#if !defined(bpf_target_arm64) && !defined(bpf_target_s390)
bpf_probe_read_kernel(&tmp, sizeof(tmp), &PT_REGS_PARM1_SYSCALL(real_regs));
#endif
arg1 = tmp;
bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));