diff options
Diffstat (limited to 'arch/loongarch/include/asm/linkage.h')
| -rw-r--r-- | arch/loongarch/include/asm/linkage.h | 36 |
1 files changed, 36 insertions, 0 deletions
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 |