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| author | Sachin Monga <smonga@linux.ibm.com> | 2024-10-30 16:43:37 -0400 |
|---|---|---|
| committer | Peter Bergner <bergner@linux.ibm.com> | 2024-10-30 16:50:04 -0400 |
| commit | 383e4f53cbd52a0e697a80a3aa7a7ef891ead8b8 (patch) | |
| tree | 362d33754e1c31454c633abf572d155a0b672b9c | |
| parent | e5ea9aef5468404eecc8c990e6852315b7d1a0e3 (diff) | |
| download | glibc-383e4f53cbd52a0e697a80a3aa7a7ef891ead8b8.tar.gz glibc-383e4f53cbd52a0e697a80a3aa7a7ef891ead8b8.tar.xz glibc-383e4f53cbd52a0e697a80a3aa7a7ef891ead8b8.zip | |
powerpc64: Obviate the need for ROP protection in clone/clone3
Save lr in a non-volatile register before scv in clone/clone3. For clone, the non-volatile register was unused and already saved/restored. Remove the dead code from clone. Signed-off-by: Sachin Monga <smonga@linux.ibm.com> Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S | 7 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S | 35 |
2 files changed, 21 insertions, 21 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S index 164311d2bd..e57cb6e82e 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S @@ -56,7 +56,6 @@ ENTRY (__clone) /* Save fn, args, stack across syscall. */ mr r30,r3 /* Function in r30. */ - mr r29,r5 /* Flags in r29. */ mr r31,r6 /* Argument in r31. */ /* 'flags' argument is first parameter to clone syscall. @@ -77,14 +76,12 @@ ENTRY (__clone) CHECK_SCV_SUPPORT r28 0f /* This is equivalent to DO_CALL_SCV, but we cannot use the macro here because it uses CFI directives and we just called cfi_endproc. */ - mflr r9 - std r9,FRAME_LR_SAVE(r1) + mflr r29 .machine "push" .machine "power9" scv 0 .machine "pop" - ld r9,FRAME_LR_SAVE(r1) - mtlr r9 + mtlr r29 /* Check for child process. */ /* When using scv, error is indicated by negative r3. */ diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S index 900c354c9c..913f341d7d 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S @@ -39,14 +39,12 @@ because it uses CFI directives and we just called cfi_endproc. */ # define DO_CLONE3_SVC_CALL(jumpfalse) \ CHECK_SCV_SUPPORT r28 jumpfalse; \ - mflr r9; \ - std r9, FRAME_LR_SAVE(r1); \ + mflr r31; \ .machine "push"; \ .machine "power9"; \ scv 0; \ .machine "pop"; \ - ld r9, FRAME_LR_SAVE(r1); \ - mtlr r9; \ + mtlr r31; \ /* With scv an, an error is a value -4095 <= x < 0. */ \ cmpdi cr1, r3, 0; \ b 1f; @@ -66,13 +64,15 @@ ENTRY(__clone3) /* Save some regs in the "red zone". */ #ifdef USE_PPC_SCV - std r28, -24(r1) - cfi_offset (r28, -24) + std r28, -32(r1) + cfi_offset (r28, -32) #endif - std r29, -16(r1) - std r30, -8(r1) - cfi_offset (r29, -16) - cfi_offset (r30, -8) + std r29, -24(r1) + std r30, -16(r1) + std r31, -8(r1) + cfi_offset (r29, -24) + cfi_offset (r30, -16) + cfi_offset (r31, -8) /* Save func and arg across syscall. */ mr r30, r5 /* Function in r30. */ @@ -132,16 +132,19 @@ L(parent): /* Parent. Restore registers & return. */ #ifdef USE_PPC_SCV - cfi_offset (r28, -24) - ld r28, -24(r1) + cfi_offset (r28, -32) + ld r28, -32(r1) cfi_restore (r28) #endif - cfi_offset (r29,-16) - cfi_offset (r30,-8) - ld r29, -16(r1) - ld r30, -8(r1) + cfi_offset (r29,-24) + cfi_offset (r30,-16) + cfi_offset (r31,-8) + ld r29, -24(r1) + ld r30, -16(r1) + ld r31, -8(r1) cfi_restore (r29) cfi_restore (r30) + cfi_restore (r31) #ifdef USE_PPC_SCV beq cr1, 0f |