From f74bd157c62f5c064418d038f9003c9c4b3dad0e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 17 Sep 2021 19:10:25 -0700 Subject: [PATCH] target/i386: Implement x86_cpu_record_sigsegv MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Record cr2, error_code, and exception_index. That last means that we must exit to cpu_loop ourselves, instead of letting exception_index being overwritten. Use the maperr parameter to properly set PG_ERROR_P_MASK. Reviewed by: Warner Losh Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- target/i386/tcg/helper-tcg.h | 6 ++++++ target/i386/tcg/tcg-cpu.c | 3 ++- target/i386/tcg/user/excp_helper.c | 23 +++++++++++++++++------ 3 files changed, 25 insertions(+), 7 deletions(-) diff --git a/target/i386/tcg/helper-tcg.h b/target/i386/tcg/helper-tcg.h index 60ca09e95e..0a4401e917 100644 --- a/target/i386/tcg/helper-tcg.h +++ b/target/i386/tcg/helper-tcg.h @@ -43,9 +43,15 @@ bool x86_cpu_exec_interrupt(CPUState *cpu, int int_req); #endif /* helper.c */ +#ifdef CONFIG_USER_ONLY +void x86_cpu_record_sigsegv(CPUState *cs, vaddr addr, + MMUAccessType access_type, + bool maperr, uintptr_t ra); +#else bool x86_cpu_tlb_fill(CPUState *cs, vaddr address, int size, MMUAccessType access_type, int mmu_idx, bool probe, uintptr_t retaddr); +#endif void breakpoint_handler(CPUState *cs); diff --git a/target/i386/tcg/tcg-cpu.c b/target/i386/tcg/tcg-cpu.c index 3ecfae34cb..6fdfdf9598 100644 --- a/target/i386/tcg/tcg-cpu.c +++ b/target/i386/tcg/tcg-cpu.c @@ -72,10 +72,11 @@ static const struct TCGCPUOps x86_tcg_ops = { .synchronize_from_tb = x86_cpu_synchronize_from_tb, .cpu_exec_enter = x86_cpu_exec_enter, .cpu_exec_exit = x86_cpu_exec_exit, - .tlb_fill = x86_cpu_tlb_fill, #ifdef CONFIG_USER_ONLY .fake_user_interrupt = x86_cpu_do_interrupt, + .record_sigsegv = x86_cpu_record_sigsegv, #else + .tlb_fill = x86_cpu_tlb_fill, .do_interrupt = x86_cpu_do_interrupt, .cpu_exec_interrupt = x86_cpu_exec_interrupt, .debug_excp_handler = breakpoint_handler, diff --git a/target/i386/tcg/user/excp_helper.c b/target/i386/tcg/user/excp_helper.c index a89b5228fd..cd507e2a1b 100644 --- a/target/i386/tcg/user/excp_helper.c +++ b/target/i386/tcg/user/excp_helper.c @@ -22,18 +22,29 @@ #include "exec/exec-all.h" #include "tcg/helper-tcg.h" -bool x86_cpu_tlb_fill(CPUState *cs, vaddr addr, int size, - MMUAccessType access_type, int mmu_idx, - bool probe, uintptr_t retaddr) +void x86_cpu_record_sigsegv(CPUState *cs, vaddr addr, + MMUAccessType access_type, + bool maperr, uintptr_t ra) { X86CPU *cpu = X86_CPU(cs); CPUX86State *env = &cpu->env; + /* + * The error_code that hw reports as part of the exception frame + * is copied to linux sigcontext.err. The exception_index is + * copied to linux sigcontext.trapno. Short of inventing a new + * place to store the trapno, we cannot let our caller raise the + * signal and set exception_index to EXCP_INTERRUPT. + */ env->cr[2] = addr; - env->error_code = (access_type == MMU_DATA_STORE) << PG_ERROR_W_BIT; - env->error_code |= PG_ERROR_U_MASK; + env->error_code = ((access_type == MMU_DATA_STORE) << PG_ERROR_W_BIT) + | (maperr ? 0 : PG_ERROR_P_MASK) + | PG_ERROR_U_MASK; cs->exception_index = EXCP0E_PAGE; + + /* Disable do_interrupt_user. */ env->exception_is_int = 0; env->exception_next_eip = -1; - cpu_loop_exit_restore(cs, retaddr); + + cpu_loop_exit_restore(cs, ra); }