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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-02-08 15:10:32 +0000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2021-02-11 23:35:11 +1100 |
| commit | fbcee2ebe8edbb6a93316f0a189ae7fcfaa7094f (patch) | |
| tree | ba1d5090e231ad571ce2c120059f08613e2c6b69 /arch/powerpc/kernel/entry_32.S | |
| parent | powerpc/syscall: Change condition to check MSR_RI (diff) | |
| download | linux-dev-fbcee2ebe8edbb6a93316f0a189ae7fcfaa7094f.tar.xz linux-dev-fbcee2ebe8edbb6a93316f0a189ae7fcfaa7094f.zip | |
powerpc/32: Always save non volatile GPRs at syscall entry
In preparation for porting syscall entry/exit to C, inconditionally
save non volatile general purpose registers.
Commit 965dd3ad3076 ("powerpc/64/syscall: Remove non-volatile GPR save
optimisation") provides detailed explanation.
This increases the number of cycles by 24 cycles on 8xx with
null_syscall benchmark (280 => 304 cycles)
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21c08162b83655195fe9ead78ff2cfd28508d023.1612796617.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 46 |
1 files changed, 1 insertions, 45 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index b1e36602c013..97dc28a68465 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -351,6 +351,7 @@ trace_syscall_entry_irq_off: .globl transfer_to_syscall transfer_to_syscall: + SAVE_NVGPRS(r1) #ifdef CONFIG_PPC_BOOK3S_32 kuep_lock r11, r12 #endif @@ -615,51 +616,6 @@ ret_from_kernel_syscall: _ASM_NOKPROBE_SYMBOL(ret_from_kernel_syscall) /* - * The fork/clone functions need to copy the full register set into - * the child process. Therefore we need to save all the nonvolatile - * registers (r13 - r31) before calling the C code. - */ - .globl ppc_fork -ppc_fork: - SAVE_NVGPRS(r1) - lwz r0,_TRAP(r1) - rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ - stw r0,_TRAP(r1) /* register set saved */ - b sys_fork - - .globl ppc_vfork -ppc_vfork: - SAVE_NVGPRS(r1) - lwz r0,_TRAP(r1) - rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ - stw r0,_TRAP(r1) /* register set saved */ - b sys_vfork - - .globl ppc_clone -ppc_clone: - SAVE_NVGPRS(r1) - lwz r0,_TRAP(r1) - rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ - stw r0,_TRAP(r1) /* register set saved */ - b sys_clone - - .globl ppc_clone3 -ppc_clone3: - SAVE_NVGPRS(r1) - lwz r0,_TRAP(r1) - rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ - stw r0,_TRAP(r1) /* register set saved */ - b sys_clone3 - - .globl ppc_swapcontext -ppc_swapcontext: - SAVE_NVGPRS(r1) - lwz r0,_TRAP(r1) - rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */ - stw r0,_TRAP(r1) /* register set saved */ - b sys_swapcontext - -/* * Top-level page fault handling. * This is in assembler because if do_page_fault tells us that * it is a bad kernel page fault, we want to save the non-volatile |