From 3674bfadb503e535250730be5df563f0d9928917 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Thu, 12 Sep 2024 11:28:21 +0200 Subject: [PATCH] linux-user/i386: Emulate orig_ax The kernel uses orig_rax/orig_eax to store the syscall number before a syscall. One can see this value in core dumps and ptrace. Reviewed-by: Richard Henderson Signed-off-by: Ilya Leoshkevich Message-ID: <20240912093012.402366-3-iii@linux.ibm.com> Signed-off-by: Richard Henderson --- linux-user/elfload.c | 4 ++-- linux-user/i386/cpu_loop.c | 3 +++ linux-user/qemu.h | 4 ++++ 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 352960b771..6cef8db3b5 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -203,7 +203,7 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State *en (*regs)[12] = tswapreg(env->regs[R_EDX]); (*regs)[13] = tswapreg(env->regs[R_ESI]); (*regs)[14] = tswapreg(env->regs[R_EDI]); - (*regs)[15] = tswapreg(env->regs[R_EAX]); /* XXX */ + (*regs)[15] = tswapreg(get_task_state(env_cpu_const(env))->orig_ax); (*regs)[16] = tswapreg(env->eip); (*regs)[17] = tswapreg(env->segs[R_CS].selector & 0xffff); (*regs)[18] = tswapreg(env->eflags); @@ -306,7 +306,7 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State *en (*regs)[8] = tswapreg(env->segs[R_ES].selector & 0xffff); (*regs)[9] = tswapreg(env->segs[R_FS].selector & 0xffff); (*regs)[10] = tswapreg(env->segs[R_GS].selector & 0xffff); - (*regs)[11] = tswapreg(env->regs[R_EAX]); /* XXX */ + (*regs)[11] = tswapreg(get_task_state(env_cpu_const(env))->orig_ax); (*regs)[12] = tswapreg(env->eip); (*regs)[13] = tswapreg(env->segs[R_CS].selector & 0xffff); (*regs)[14] = tswapreg(env->eflags); diff --git a/linux-user/i386/cpu_loop.c b/linux-user/i386/cpu_loop.c index 92beb6830c..7a35215278 100644 --- a/linux-user/i386/cpu_loop.c +++ b/linux-user/i386/cpu_loop.c @@ -172,6 +172,7 @@ static void emulate_vsyscall(CPUX86State *env) /* * Perform the syscall. None of the vsyscalls should need restarting. */ + get_task_state(env_cpu(env))->orig_ax = syscall; ret = do_syscall(env, syscall, env->regs[R_EDI], env->regs[R_ESI], env->regs[R_EDX], env->regs[10], env->regs[8], env->regs[9], 0, 0); @@ -221,6 +222,7 @@ void cpu_loop(CPUX86State *env) case EXCP_SYSCALL: #endif /* linux syscall from int $0x80 */ + get_task_state(cs)->orig_ax = env->regs[R_EAX]; ret = do_syscall(env, env->regs[R_EAX], env->regs[R_EBX], @@ -239,6 +241,7 @@ void cpu_loop(CPUX86State *env) #ifdef TARGET_X86_64 case EXCP_SYSCALL: /* linux syscall from syscall instruction. */ + get_task_state(cs)->orig_ax = env->regs[R_EAX]; ret = do_syscall(env, env->regs[R_EAX], env->regs[R_EDI], diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 98ad848ab2..895bdd722a 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -113,6 +113,10 @@ struct TaskState { struct target_vm86plus_struct vm86plus; uint32_t v86flags; uint32_t v86mask; +#endif +#if defined(TARGET_I386) + /* Last syscall number. */ + target_ulong orig_ax; #endif abi_ulong child_tidptr; #ifdef TARGET_M68K