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powerpc/32s: Move KUEP locking/unlocking in C

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This can be done in C, do it.

Unrolling the loop gains approx. 15% performance.

From now on, prepare_transfer_to_handler() is only for
interrupts from kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4eadd873927e9a73c3d1dfe2f9497353465514cf.1615552867.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-03-12 12:50:47 +00:00 • committed by Michael Ellerman
parent a2b3e09ae4
commit b5efec00b6
9 changed files with 64 additions and 48 deletions
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31
arch/powerpc/include/asm/book3s/32/kup.h
View file

@ -7,37 +7,6 @@
#ifdef __ASSEMBLY__
.macro kuep_update_sr gpr1, gpr2 /* NEVER use r0 as gpr2 due to addis */
101: mtsrin \gpr1, \gpr2
addi \gpr1, \gpr1, 0x111 /* next VSID */
rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
addis \gpr2, \gpr2, 0x1000 /* address of next segment */
bdnz 101b
isync
.endm
.macro kuep_lock gpr1, gpr2
#ifdef CONFIG_PPC_KUEP
li \gpr1, NUM_USER_SEGMENTS
li \gpr2, 0
mtctr \gpr1
mfsrin \gpr1, \gpr2
oris \gpr1, \gpr1, SR_NX@h /* set Nx */
kuep_update_sr \gpr1, \gpr2
#endif
.endm
.macro kuep_unlock gpr1, gpr2
#ifdef CONFIG_PPC_KUEP
li \gpr1, NUM_USER_SEGMENTS
li \gpr2, 0
mtctr \gpr1
mfsrin \gpr1, \gpr2
rlwinm \gpr1, \gpr1, 0, ~SR_NX /* Clear Nx */
kuep_update_sr \gpr1, \gpr2
#endif
.endm
#ifdef CONFIG_PPC_KUAP
.macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */

6
arch/powerpc/include/asm/interrupt.h
View file

@ -33,8 +33,10 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
if (!arch_irq_disabled_regs(regs))
trace_hardirqs_off();
if (user_mode(regs))
if (user_mode(regs)) {
kuep_lock();
account_cpu_user_entry();
}
#endif
/*
* Book3E reconciles irq soft mask in asm
@ -89,6 +91,8 @@ static inline void interrupt_exit_prepare(struct pt_regs *regs, struct interrupt
exception_exit(state->ctx_state);
#endif
if (user_mode(regs))
kuep_unlock();
/*
* Book3S exits to user via interrupt_exit_user_prepare(), which does
* context tracking, which is a cleaner way to handle PREEMPT=y

8
arch/powerpc/include/asm/kup.h
View file

@ -55,6 +55,14 @@ void setup_kuep(bool disabled);
static inline void setup_kuep(bool disabled) { }
#endif /* CONFIG_PPC_KUEP */
#if defined(CONFIG_PPC_KUEP) && defined(CONFIG_PPC_BOOK3S_32)
void kuep_lock(void);
void kuep_unlock(void);
#else
static inline void kuep_lock(void) { }
static inline void kuep_unlock(void) { }
#endif
#ifdef CONFIG_PPC_KUAP
void setup_kuap(bool disabled);
#else