Commit fbcee2eb authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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 965dd3ad ("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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21c08162b83655195fe9ead78ff2cfd28508d023.1612796617.git.christophe.leroy@csgroup.eu
parent c01b9166

arch/powerpc/kernel/entry_32.S

+1 −45
Original line number Diff line number Diff line
@@ -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
@@ -614,51 +615,6 @@ ret_from_kernel_syscall: 
#endif

_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

arch/powerpc/kernel/head_32.h

+1 −1
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ 
	stw	r2,GPR2(r11)

	addi	r10,r10,STACK_FRAME_REGS_MARKER@l

	stw	r9,_MSR(r11)

	li	r2, \trapno + 1

	li	r2, \trapno

	stw	r10,8(r11)

	stw	r2,_TRAP(r11)

	SAVE_GPR(0, r11)

arch/powerpc/kernel/head_booke.h

+1 −1
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) 
	stw	r2,GPR2(r11)

	addi	r12, r12, STACK_FRAME_REGS_MARKER@l

	stw	r9,_MSR(r11)

	li	r2, \trapno + 1

	li	r2, \trapno

	stw	r12, 8(r11)

	stw	r2,_TRAP(r11)

	SAVE_GPR(0, r11)

arch/powerpc/kernel/syscalls/syscall.tbl

+5 −15
Original line number Diff line number Diff line
@@ -9,9 +9,7 @@ 
#

0	nospu	restart_syscall			sys_restart_syscall

1	nospu	exit				sys_exit

2	32	fork				ppc_fork			sys_fork

2	64	fork				sys_fork

2	spu	fork				sys_ni_syscall

2	nospu	fork				sys_fork

3	common	read				sys_read

4	common	write				sys_write

5	common	open				sys_open			compat_sys_open
@@ -160,9 +158,7 @@ 
119	32	sigreturn			sys_sigreturn			compat_sys_sigreturn

119	64	sigreturn			sys_ni_syscall

119	spu	sigreturn			sys_ni_syscall

120	32	clone				ppc_clone			sys_clone

120	64	clone				sys_clone

120	spu	clone				sys_ni_syscall

120	nospu	clone				sys_clone

121	common	setdomainname			sys_setdomainname

122	common	uname				sys_newuname

123	common	modify_ldt			sys_ni_syscall
@@ -244,9 +240,7 @@ 
186	spu	sendfile			sys_sendfile64

187	common	getpmsg				sys_ni_syscall

188	common 	putpmsg				sys_ni_syscall

189	32	vfork				ppc_vfork			sys_vfork

189	64	vfork				sys_vfork

189	spu	vfork				sys_ni_syscall

189	nospu	vfork				sys_vfork

190	common	ugetrlimit			sys_getrlimit			compat_sys_getrlimit

191	common	readahead			sys_readahead			compat_sys_readahead

192	32	mmap2				sys_mmap2			compat_sys_mmap2
@@ -322,9 +316,7 @@ 
248	32	clock_nanosleep			sys_clock_nanosleep_time32

248	64	clock_nanosleep			sys_clock_nanosleep

248	spu	clock_nanosleep			sys_clock_nanosleep

249	32	swapcontext			ppc_swapcontext			compat_sys_swapcontext

249	64	swapcontext			sys_swapcontext

249	spu	swapcontext			sys_ni_syscall

249	nospu	swapcontext			sys_swapcontext			compat_sys_swapcontext

250	common	tgkill				sys_tgkill

251	32	utimes				sys_utimes_time32

251	64	utimes				sys_utimes
@@ -522,9 +514,7 @@ 
432	common	fsmount				sys_fsmount

433	common	fspick				sys_fspick

434	common	pidfd_open			sys_pidfd_open

435	32	clone3				ppc_clone3			sys_clone3

435	64	clone3				sys_clone3

435	spu	clone3				sys_ni_syscall

435	nospu	clone3				sys_clone3

436	common	close_range			sys_close_range

437	common	openat2				sys_openat2

438	common	pidfd_getfd			sys_pidfd_getfd