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Subject[RFC PATCH v1 41/41] powerpc/32: Manage KUAP in C
Date
Move all KUAP management in C.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/kup.h | 50 +-------------------
arch/powerpc/include/asm/interrupt.h | 2 +
arch/powerpc/include/asm/kup.h | 19 +-------
arch/powerpc/include/asm/nohash/32/kup-8xx.h | 25 +---------
arch/powerpc/kernel/entry_32.S | 6 ---
arch/powerpc/kernel/interrupt.c | 19 ++------
arch/powerpc/kernel/process.c | 3 ++
7 files changed, 12 insertions(+), 112 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index c9d6c28bcd10..27991e0d2cf9 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -5,55 +5,7 @@
#include <asm/bug.h>
#include <asm/book3s/32/mmu-hash.h>

-#ifdef __ASSEMBLY__
-
-#ifdef CONFIG_PPC_KUAP
-
-.macro kuap_update_sr gpr1, gpr2, gpr3 /* 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 */
- cmplw \gpr2, \gpr3
- blt- 101b
- isync
-.endm
-
-.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
- lwz \gpr2, KUAP(\thread)
- rlwinm. \gpr3, \gpr2, 28, 0xf0000000
- stw \gpr2, STACK_REGS_KUAP(\sp)
- beq+ 102f
- li \gpr1, 0
- stw \gpr1, KUAP(\thread)
- mfsrin \gpr1, \gpr2
- oris \gpr1, \gpr1, SR_KS@h /* set Ks */
- kuap_update_sr \gpr1, \gpr2, \gpr3
-102:
-.endm
-
-.macro kuap_restore sp, current, gpr1, gpr2, gpr3
- lwz \gpr2, STACK_REGS_KUAP(\sp)
- rlwinm. \gpr3, \gpr2, 28, 0xf0000000
- stw \gpr2, THREAD + KUAP(\current)
- beq+ 102f
- mfsrin \gpr1, \gpr2
- rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
- kuap_update_sr \gpr1, \gpr2, \gpr3
-102:
-.endm
-
-.macro kuap_check current, gpr
-#ifdef CONFIG_PPC_KUAP_DEBUG
- lwz \gpr, THREAD + KUAP(\current)
-999: twnei \gpr, 0
- EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
-#endif
-.endm
-
-#endif /* CONFIG_PPC_KUAP */
-
-#else /* !__ASSEMBLY__ */
+#ifndef __ASSEMBLY__

#ifdef CONFIG_PPC_KUAP

diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index e5e04e962165..0e38185d4d90 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -24,6 +24,8 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
kuep_lock();
current->thread.regs = regs;
account_cpu_user_entry();
+ } else {
+ kuap_save_and_lock(regs);
}
#endif
/*
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index b7efa46b3109..f463256a57a6 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -26,24 +26,7 @@
#include <asm/book3s/32/kup.h>
#endif

-#ifdef __ASSEMBLY__
-#ifndef CONFIG_PPC_KUAP
-.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
-.endm
-
-.macro kuap_restore sp, current, gpr1, gpr2, gpr3
-.endm
-
-.macro kuap_check current, gpr
-.endm
-
-.macro kuap_check_amr gpr1, gpr2
-.endm
-
-#endif
-
-#else /* !__ASSEMBLY__ */
-
+#ifndef __ASSEMBLY__
extern bool disable_kuep;
extern bool disable_kuap;

diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
index 6f191fe08a2e..add0413f31d4 100644
--- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
@@ -7,30 +7,7 @@

#ifdef CONFIG_PPC_KUAP

-#ifdef __ASSEMBLY__
-
-.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
- lis \gpr2, MD_APG_KUAP@h /* only APG0 and APG1 are used */
- mfspr \gpr1, SPRN_MD_AP
- mtspr SPRN_MD_AP, \gpr2
- stw \gpr1, STACK_REGS_KUAP(\sp)
-.endm
-
-.macro kuap_restore sp, current, gpr1, gpr2, gpr3
- lwz \gpr1, STACK_REGS_KUAP(\sp)
- mtspr SPRN_MD_AP, \gpr1
-.endm
-
-.macro kuap_check current, gpr
-#ifdef CONFIG_PPC_KUAP_DEBUG
- mfspr \gpr, SPRN_MD_AP
- rlwinm \gpr, \gpr, 16, 0xffff
-999: twnei \gpr, MD_APG_KUAP@h
- EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
-#endif
-.endm
-
-#else /* !__ASSEMBLY__ */
+#ifndef __ASSEMBLY__

#include <asm/reg.h>

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 3ae790a362d1..2f3b41c8b23f 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -59,13 +59,11 @@
.globl prepare_transfer_to_handler
prepare_transfer_to_handler:
andi. r0,r9,MSR_PR
- addi r12, r2, THREAD
bnelr

/* if from kernel, check interrupted DOZE/NAP mode and
* check for stack overflow
*/
- kuap_save_and_lock r11, r12, r9, r5, r6
lwz r12,TI_LOCAL_FLAGS(r2)
mtcrf 0x01,r12
bt- 31-TLF_NAPPING,4f
@@ -105,7 +103,6 @@ ret_from_syscall:
cmplwi cr0,r5,0
bne- 2f
#endif /* CONFIG_PPC_47x */
- kuap_check r2, r4
lwz r4,_LINK(r1)
lwz r5,_CCR(r1)
mtlr r4
@@ -217,7 +214,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE)
stw r10,_CCR(r1)
stw r1,KSP(r3) /* Set old stack pointer */

- kuap_check r2, r0
#ifdef CONFIG_SMP
/* We need a sync somewhere here to make sure that if the
* previous task gets rescheduled on another CPU, it sees all
@@ -285,7 +281,6 @@ interrupt_return:
bne- .Lrestore_nvgprs

.Lfast_user_interrupt_return:
- kuap_check r2, r4
lwz r11,_NIP(r1)
lwz r12,_MSR(r1)
mtspr SPRN_SRR0,r11
@@ -330,7 +325,6 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)

.Lfast_kernel_interrupt_return:
cmpwi cr1,r3,0
- kuap_restore r1, r2, r3, r4, r5
lwz r11,_NIP(r1)
lwz r12,_MSR(r1)
mtspr SPRN_SRR0,r11
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index 8180ed261a27..42769d619f7d 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -31,6 +31,9 @@ notrace long system_call_exception(long r3, long r4, long r5,
unsigned long expected_msr;

kuep_lock();
+#ifdef CONFIG_PPC32
+ kuap_save_and_lock(regs);
+#endif

regs->orig_gpr3 = r3;

@@ -74,9 +77,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
isync();
} else
#endif
-#ifdef CONFIG_PPC64
kuap_check();
-#endif

#ifdef CONFIG_PPC_ADV_DEBUG_REGS
if (IS_ENABLED(CONFIG_PPC32) && unlikely(current->thread.debug.dbcr0 & DBCR0_IDM)) {
@@ -240,9 +241,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,

CT_WARN_ON(ct_state() == CONTEXT_USER);

-#ifdef CONFIG_PPC64
kuap_check();
-#endif

regs->result = r3;

@@ -351,7 +350,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,

account_cpu_user_exit();

-#ifdef CONFIG_PPC_BOOK3S_64 /* BOOK3E and ppc32 not using this */
+#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not using this */
/*
* We do this at the end so that we do context switch with KERNEL AMR
*/
@@ -380,9 +379,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
* We don't need to restore AMR on the way back to userspace for KUAP.
* AMR can only have been unlocked if we interrupted the kernel.
*/
-#ifdef CONFIG_PPC64
kuap_check();
-#endif

local_irq_save(flags);

@@ -453,9 +450,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
/*
* We do this at the end so that we do context switch with KERNEL AMR
*/
-#ifdef CONFIG_PPC64
kuap_user_restore(regs);
-#endif
return ret;
}

@@ -466,9 +461,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
{
unsigned long flags;
unsigned long ret = 0;
-#ifdef CONFIG_PPC64
unsigned long kuap;
-#endif

if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x) &&
unlikely(!(regs->msr & MSR_RI)))
@@ -482,9 +475,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
if (TRAP(regs) != 0x700)
CT_WARN_ON(ct_state() == CONTEXT_USER);

-#ifdef CONFIG_PPC64
kuap = kuap_get_and_check();
-#endif

if (unlikely(current_thread_info()->flags & _TIF_EMULATE_STACK_STORE)) {
clear_bits(_TIF_EMULATE_STACK_STORE, &current_thread_info()->flags);
@@ -526,9 +517,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
* which would cause Read-After-Write stalls. Hence, we take the AMR
* value from the check above.
*/
-#ifdef CONFIG_PPC64
kuap_kernel_restore(regs, kuap);
-#endif

return ret;
}
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 384951381329..dda871dd9bfb 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1255,6 +1255,9 @@ struct task_struct *__switch_to(struct task_struct *prev,
*/
restore_sprs(old_thread, new_thread);

+#ifdef CONFIG_PPC32
+ kuap_check();
+#endif
last = _switch(old_thread, new_thread);

#ifdef CONFIG_PPC_BOOK3S_64
--
2.25.0
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