From 3c62b5d2015b8292d4453f8174abf5fadbc6cc0f Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 29 Sep 2021 09:05:47 -0400 Subject: [PATCH] linux-user/riscv: Implement setup_sigtramp MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Reviewed-by: Alistair Francis Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson Message-Id: <20210929130553.121567-21-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/riscv/signal.c | 22 +++++++++++++--------- linux-user/riscv/target_signal.h | 2 ++ 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c index f7f33bc90a..a0f9542ce3 100644 --- a/linux-user/riscv/signal.c +++ b/linux-user/riscv/signal.c @@ -47,7 +47,6 @@ 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; }; @@ -105,12 +104,6 @@ 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) @@ -127,14 +120,13 @@ 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; @@ -203,3 +195,15 @@ 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); +} 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 */