diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc64/sysdep.h')
| -rw-r--r-- | sysdeps/powerpc/powerpc64/sysdep.h | 120 |
1 files changed, 114 insertions, 6 deletions
diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h index d557098..f6a0619 100644 --- a/sysdeps/powerpc/powerpc64/sysdep.h +++ b/sysdeps/powerpc/powerpc64/sysdep.h @@ -17,6 +17,7 @@ <https://www.gnu.org/licenses/>. */ #include <sysdeps/powerpc/sysdep.h> +#include <tls.h> #ifdef __ASSEMBLER__ @@ -263,10 +264,80 @@ LT_LABELSUFFIX(name,_name_end): ; \ TRACEBACK_MASK(name,mask); \ END_2(name) -#define DO_CALL(syscall) \ - li 0,syscall; \ +/* We will allocate a new frame to save LR and the non-volatile register used to + read the TCB when checking for scv support on syscall code. We actually just + need the minimum frame size plus room for 1 reg (8 bytes). But the ABI + mandates stack frames should be aligned at 16 Bytes, so we end up allocating + a bit more space then what will actually be used. */ +#define SCV_FRAME_SIZE (FRAME_MIN_SIZE+16) +#define SCV_FRAME_NVOLREG_SAVE FRAME_MIN_SIZE + +/* Allocate frame and save register */ +#define NVOLREG_SAVE \ + stdu r1,-SCV_FRAME_SIZE(r1); \ + std r31,SCV_FRAME_NVOLREG_SAVE(r1); \ + cfi_adjust_cfa_offset(SCV_FRAME_SIZE); + +/* Restore register and destroy frame */ +#define NVOLREG_RESTORE \ + ld r31,SCV_FRAME_NVOLREG_SAVE(r1); \ + addi r1,r1,SCV_FRAME_SIZE; \ + cfi_adjust_cfa_offset(-SCV_FRAME_SIZE); + +/* Check PPC_FEATURE2_SCV bit from hwcap2 in the TCB. If it is not set, scv is + not available, then go to JUMPFALSE (label given by the macro's caller). We + save the value we read from the TCB in a non-volatile register so we can + reuse it later when exiting from the syscall in PSEUDO_RET. Note that for + the static case we need an extra check to guarantee the thread pointer has + already been initialized, otherwise we may try to access an invalid address + if a syscall is called before the TLS has been setup. */ + .macro CHECK_SCV_SUPPORT REG JUMPFALSE + +#ifndef SHARED + /* Check if thread pointer has already been setup. */ + cmpdi r13,0 + beq \JUMPFALSE +#endif + + /* Read PPC_FEATURE2_SCV from TCB and store it in REG */ + ld \REG,TCB_HWCAP(PT_THREAD_POINTER) + andis. \REG,\REG,PPC_FEATURE2_SCV>>16 + + beq \JUMPFALSE + .endm + +#if IS_IN(rtld) +# define DO_CALL(syscall) \ + li r0,syscall; \ + DO_CALL_SC +#else +/* Before doing the syscall, check if we can use scv. scv is supported by P9 + and later with Linux v5.9 and later. If so, use it. Otherwise, fallback to + sc. We use a non-volatile register to save hwcap2 from the TCB, so we need + to save its content beforehand. */ +# define DO_CALL(syscall) \ + li r0,syscall; \ + NVOLREG_SAVE; \ + CHECK_SCV_SUPPORT r31 0f; \ + DO_CALL_SCV; \ + b 1f; \ +0: DO_CALL_SC; \ +1: +#endif /* IS_IN(rtld) */ + +/* DO_CALL_SC and DO_CALL_SCV expect the syscall number to be in r0. */ +#define DO_CALL_SC \ sc +#define DO_CALL_SCV \ + mflr r9; \ + std r9,FRAME_LR_SAVE(r1); \ + cfi_offset(lr,FRAME_LR_SAVE); \ + scv 0; \ + ld r9,FRAME_LR_SAVE(r1); \ + mtlr r9; \ + cfi_restore(lr); + /* ppc64 is always PIC */ #undef JUMPTARGET #define JUMPTARGET(name) FUNC_LABEL(name) @@ -304,9 +375,32 @@ LT_LABELSUFFIX(name,_name_end): ; \ .endif #endif -#define PSEUDO_RET \ - bnslr+; \ +#if IS_IN(rtld) +# define PSEUDO_RET \ + RET_SC; \ TAIL_CALL_SYSCALL_ERROR +#else +/* This should only be called after a DO_CALL. In such cases, r31 contains the + value of PPC_FEATURE2_SCV read from hwcap2 by CHECK_SCV_SUPPORT. If it is + set, we know we have entered the kernel using scv, so handle the return code + accordingly. */ +# define PSEUDO_RET \ + cmpdi cr5,r31,0; \ + NVOLREG_RESTORE; \ + beq cr5,0f; \ + RET_SCV; \ + b 1f; \ +0: RET_SC; \ +1: TAIL_CALL_SYSCALL_ERROR +#endif + +#define RET_SCV \ + cmpdi r3,0; \ + bgelr+; \ + neg r3,r3; + +#define RET_SC \ + bnslr+; #define ret PSEUDO_RET @@ -319,8 +413,15 @@ LT_LABELSUFFIX(name,_name_end): ; \ ENTRY (name); \ DO_CALL (SYS_ify (syscall_name)) -#define PSEUDO_RET_NOERRNO \ +#if IS_IN(rtld) +# define PSEUDO_RET_NOERRNO \ blr +#else +/* This should only be called after a DO_CALL. */ +# define PSEUDO_RET_NOERRNO \ + NVOLREG_RESTORE; \ + blr +#endif /* IS_IN(rtld) */ #define ret_NOERRNO PSEUDO_RET_NOERRNO @@ -333,8 +434,15 @@ LT_LABELSUFFIX(name,_name_end): ; \ ENTRY (name); \ DO_CALL (SYS_ify (syscall_name)) -#define PSEUDO_RET_ERRVAL \ +#if IS_IN(rtld) +# define PSEUDO_RET_ERRVAL \ + blr +#else +/* This should only be called after a DO_CALL. */ +# define PSEUDO_RET_ERRVAL \ + NVOLREG_RESTORE; \ blr +#endif /* IS_IN(rtld) */ #define ret_ERRVAL PSEUDO_RET_ERRVAL |