diff --git a/arch/loongarch/include/asm/linkage.h b/arch/loongarch/include/asm/linkage.h index e2eca1a25b4e..a1bd6a3ee03a 100644 --- a/arch/loongarch/include/asm/linkage.h +++ b/arch/loongarch/include/asm/linkage.h @@ -41,4 +41,40 @@ .cfi_endproc; \ SYM_END(name, SYM_T_NONE) +/* + * This is for the signal handler trampoline, which is used as the return + * address of the signal handlers in userspace instead of called normally. + * The long standing libgcc bug https://gcc.gnu.org/PR124050 requires a + * nop between .cfi_startproc and the actual address of the trampoline, so + * we cannot simply use SYM_FUNC_START. + * + * This wrapper also contains all the .cfi_* directives for recovering + * the content of the GPRs and the "return address" (where the rt_sigreturn + * syscall will jump to), assuming there is a struct rt_sigframe (where + * a struct sigcontext containing those information we need to recover) at + * $sp. The "DWARF for the LoongArch(TM) Architecture" manual states + * column 0 is for $zero, but it does not make too much sense to + * save/restore the hardware zero register. Repurpose this column here + * for the return address (here it's not the content of $ra we cannot use + * the default column 3). + */ +#define SYM_SIGFUNC_START(name) \ + .cfi_startproc; \ + .cfi_signal_frame; \ + .cfi_def_cfa 3, RT_SIGFRAME_SC; \ + .cfi_return_column 0; \ + .cfi_offset 0, SC_PC; \ + \ + .irp num, 1, 2, 3, 4, 5, 6, 7, 8, \ + 9, 10, 11, 12, 13, 14, 15, 16, \ + 17, 18, 19, 20, 21, 22, 23, 24, \ + 25, 26, 27, 28, 29, 30, 31; \ + .cfi_offset \num, SC_REGS + \num * SZREG; \ + .endr; \ + \ + nop; \ + SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) + +#define SYM_SIGFUNC_END(name) SYM_FUNC_END(name) + #endif diff --git a/arch/loongarch/include/asm/sigframe.h b/arch/loongarch/include/asm/sigframe.h new file mode 100644 index 000000000000..109298b8d7e0 --- /dev/null +++ b/arch/loongarch/include/asm/sigframe.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#include +#include + +struct rt_sigframe { + struct siginfo rs_info; + struct ucontext rs_uctx; +}; diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c index 3017c7157600..2cc953f113ac 100644 --- a/arch/loongarch/kernel/asm-offsets.c +++ b/arch/loongarch/kernel/asm-offsets.c @@ -16,6 +16,7 @@ #include #include #include +#include #include static void __used output_ptreg_defines(void) @@ -220,6 +221,7 @@ static void __used output_sc_defines(void) COMMENT("Linux sigcontext offsets."); OFFSET(SC_REGS, sigcontext, sc_regs); OFFSET(SC_PC, sigcontext, sc_pc); + OFFSET(RT_SIGFRAME_SC, rt_sigframe, rs_uctx.uc_mcontext); BLANK(); } diff --git a/arch/loongarch/kernel/signal.c b/arch/loongarch/kernel/signal.c index c9f7ca778364..d4151d2fb82e 100644 --- a/arch/loongarch/kernel/signal.c +++ b/arch/loongarch/kernel/signal.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -51,11 +52,6 @@ #define lock_lbt_owner() ({ preempt_disable(); pagefault_disable(); }) #define unlock_lbt_owner() ({ pagefault_enable(); preempt_enable(); }) -struct rt_sigframe { - struct siginfo rs_info; - struct ucontext rs_uctx; -}; - struct _ctx_layout { struct sctx_info *addr; unsigned int size; diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile index 520f1513f07d..294c16b9517f 100644 --- a/arch/loongarch/vdso/Makefile +++ b/arch/loongarch/vdso/Makefile @@ -26,7 +26,7 @@ cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ -std=gnu11 -fms-extensions -O2 -g -fno-strict-aliasing -fno-common -fno-builtin \ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ - $(call cc-option, -fno-asynchronous-unwind-tables) \ + $(call cc-option, -fasynchronous-unwind-tables) \ $(call cc-option, -fno-stack-protector) aflags-vdso := $(ccflags-vdso) \ -D__ASSEMBLY__ -Wa,-gdwarf-2 @@ -41,7 +41,7 @@ endif # VDSO linker flags. ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \ - $(filter -E%,$(KBUILD_CFLAGS)) -shared --build-id -T + $(filter -E%,$(KBUILD_CFLAGS)) -shared --build-id --eh-frame-hdr -T # # Shared build commands. diff --git a/arch/loongarch/vdso/sigreturn.S b/arch/loongarch/vdso/sigreturn.S index 9cb3c58fad03..59f940d928de 100644 --- a/arch/loongarch/vdso/sigreturn.S +++ b/arch/loongarch/vdso/sigreturn.S @@ -12,13 +12,13 @@ #include #include +#include .section .text - .cfi_sections .debug_frame -SYM_FUNC_START(__vdso_rt_sigreturn) +SYM_SIGFUNC_START(__vdso_rt_sigreturn) li.w a7, __NR_rt_sigreturn syscall 0 -SYM_FUNC_END(__vdso_rt_sigreturn) +SYM_SIGFUNC_END(__vdso_rt_sigreturn)