| Message ID | 20210616011209.1446045-17-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | linux-user: Move signal trampolines to new page | expand |
On 6/16/21 3:12 AM, Richard Henderson wrote: > Create and record the rt signal trampoline. > > This fixes a bug wrt libgcc fallback unwinding. It expects > the stack pointer to point to the siginfo_t, whereas we had > inexplicably placed our private signal trampoline at the start > of the signal frame instead of the end. Now moot because we > have removed it from the stack frame entirely. > > Cc: qemu-riscv@nongnu.org > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > linux-user/riscv/target_signal.h | 2 ++ > linux-user/riscv/signal.c | 22 +++++++++++++--------- > 2 files changed, 15 insertions(+), 9 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
On Wed, Jun 16, 2021 at 11:22 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > Create and record the rt signal trampoline. > > This fixes a bug wrt libgcc fallback unwinding. It expects > the stack pointer to point to the siginfo_t, whereas we had > inexplicably placed our private signal trampoline at the start > of the signal frame instead of the end. Now moot because we > have removed it from the stack frame entirely. > > Cc: qemu-riscv@nongnu.org > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Alistair > --- > linux-user/riscv/target_signal.h | 2 ++ > linux-user/riscv/signal.c | 22 +++++++++++++--------- > 2 files changed, 15 insertions(+), 9 deletions(-) > > diff --git a/linux-user/riscv/target_signal.h b/linux-user/riscv/target_signal.h > index f113ba9a55..3e36fddc9d 100644 > --- a/linux-user/riscv/target_signal.h > +++ b/linux-user/riscv/target_signal.h > @@ -15,4 +15,6 @@ typedef struct target_sigaltstack { > > #include "../generic/signal.h" > > +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1 > + > #endif /* RISCV_TARGET_SIGNAL_H */ > diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c > index 9405c7fd9a..4086dfa5d5 100644 > --- a/linux-user/riscv/signal.c > +++ b/linux-user/riscv/signal.c > @@ -46,7 +46,6 @@ struct target_ucontext { > }; > > struct target_rt_sigframe { > - uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */ > struct target_siginfo info; > struct target_ucontext uc; > }; > @@ -104,12 +103,6 @@ static void setup_ucontext(struct target_ucontext *uc, > setup_sigcontext(&uc->uc_mcontext, env); > } > > -static inline void install_sigtramp(uint32_t *tramp) > -{ > - __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ > - __put_user(0x00000073, tramp + 1); /* ecall */ > -} > - > void setup_rt_frame(int sig, struct target_sigaction *ka, > target_siginfo_t *info, > target_sigset_t *set, CPURISCVState *env) > @@ -126,14 +119,13 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, > > setup_ucontext(&frame->uc, env, set); > tswap_siginfo(&frame->info, info); > - install_sigtramp(frame->tramp); > > env->pc = ka->_sa_handler; > env->gpr[xSP] = frame_addr; > env->gpr[xA0] = sig; > env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info); > env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc); > - env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp); > + env->gpr[xRA] = default_rt_sigreturn; > > return; > > @@ -202,3 +194,15 @@ badframe: > force_sig(TARGET_SIGSEGV); > return 0; > } > + > +void setup_sigtramp(abi_ulong sigtramp_page) > +{ > + uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0); > + assert(tramp != NULL); > + > + __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ > + __put_user(0x00000073, tramp + 1); /* ecall */ > + > + default_rt_sigreturn = sigtramp_page; > + unlock_user(tramp, sigtramp_page, 8); > +} > -- > 2.25.1 > >
diff --git a/linux-user/riscv/target_signal.h b/linux-user/riscv/target_signal.h index f113ba9a55..3e36fddc9d 100644 --- a/linux-user/riscv/target_signal.h +++ b/linux-user/riscv/target_signal.h @@ -15,4 +15,6 @@ typedef struct target_sigaltstack { #include "../generic/signal.h" +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 1 + #endif /* RISCV_TARGET_SIGNAL_H */ diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c index 9405c7fd9a..4086dfa5d5 100644 --- a/linux-user/riscv/signal.c +++ b/linux-user/riscv/signal.c @@ -46,7 +46,6 @@ struct target_ucontext { }; struct target_rt_sigframe { - uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */ struct target_siginfo info; struct target_ucontext uc; }; @@ -104,12 +103,6 @@ static void setup_ucontext(struct target_ucontext *uc, setup_sigcontext(&uc->uc_mcontext, env); } -static inline void install_sigtramp(uint32_t *tramp) -{ - __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ - __put_user(0x00000073, tramp + 1); /* ecall */ -} - void setup_rt_frame(int sig, struct target_sigaction *ka, target_siginfo_t *info, target_sigset_t *set, CPURISCVState *env) @@ -126,14 +119,13 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, setup_ucontext(&frame->uc, env, set); tswap_siginfo(&frame->info, info); - install_sigtramp(frame->tramp); env->pc = ka->_sa_handler; env->gpr[xSP] = frame_addr; env->gpr[xA0] = sig; env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info); env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc); - env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp); + env->gpr[xRA] = default_rt_sigreturn; return; @@ -202,3 +194,15 @@ badframe: force_sig(TARGET_SIGSEGV); return 0; } + +void setup_sigtramp(abi_ulong sigtramp_page) +{ + uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0); + assert(tramp != NULL); + + __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ + __put_user(0x00000073, tramp + 1); /* ecall */ + + default_rt_sigreturn = sigtramp_page; + unlock_user(tramp, sigtramp_page, 8); +}
Create and record the rt signal trampoline. This fixes a bug wrt libgcc fallback unwinding. It expects the stack pointer to point to the siginfo_t, whereas we had inexplicably placed our private signal trampoline at the start of the signal frame instead of the end. Now moot because we have removed it from the stack frame entirely. Cc: qemu-riscv@nongnu.org Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- linux-user/riscv/target_signal.h | 2 ++ linux-user/riscv/signal.c | 22 +++++++++++++--------- 2 files changed, 15 insertions(+), 9 deletions(-) -- 2.25.1