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Commit 2c74e258 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
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powerpc/40x: Rework 40x PTE access and TLB miss 

Commit 1bc54c03 ("powerpc: rework 4xx PTE access and TLB miss")
reworked 44x PTE access to avoid atomic pte updates, and
left 8xx, 40x and fsl booke with atomic pte updates.
Commit 6cfd8990 ("powerpc: rework FSL Book-E PTE access and TLB
miss") removed atomic pte updates on fsl booke.
It went away on 8xx with commit ddfc20a3 ("powerpc/8xx: Remove
PTE_ATOMIC_UPDATES").

40x is the last platform setting PTE_ATOMIC_UPDATES.

Rework PTE access and TLB miss to remove PTE_ATOMIC_UPDATES for 40x:
- Always handle DSI as a fault.
- Bail out of TLB miss handler when CONFIG_SWAP is set and
_PAGE_ACCESSED is not set.
- Bail out of ITLB miss handler when _PAGE_EXEC is not set.
- Only set WR bit when both _PAGE_RW and _PAGE_DIRTY are set.
- Remove _PAGE_HWWRITE
- Don't require PTE_ATOMIC_UPDATES anymore
Reported-by: default avatarkbuild test robot <lkp@intel.com>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/99a0fcd337ef67088140d1647d75fea026a70413.1590079968.git.christophe.leroy@csgroup.eu
parent f16dca3e
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Showing with 34 additions and 172 deletions
arch/powerpc/include/asm/nohash/32/pte-40x.h
View file @ 2c74e258
......@@ -44,9 +44,8 @@
#define _PAGE_WRITETHRU 0x008 /* W: caching is write-through */
#define _PAGE_USER 0x010 /* matches one of the zone permission bits */
#define _PAGE_SPECIAL 0x020 /* software: Special page */
#define _PAGE_RW 0x040 /* software: Writes permitted */
#define _PAGE_DIRTY 0x080 /* software: dirty page */
#define _PAGE_HWWRITE 0x100 /* hardware: Dirty & RW, set in exception */
#define _PAGE_RW 0x100 /* hardware: WR, anded with dirty in exception */
#define _PAGE_EXEC 0x200 /* hardware: EX permission */
#define _PAGE_ACCESSED 0x400 /* software: R: page referenced */
......@@ -58,8 +57,8 @@
#define _PAGE_KERNEL_RO 0
#define _PAGE_KERNEL_ROX _PAGE_EXEC
#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE | _PAGE_EXEC)
#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW)
#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC)
#define _PMD_PRESENT 0x400 /* PMD points to page of PTEs */
#define _PMD_PRESENT_MASK _PMD_PRESENT
......@@ -85,21 +84,5 @@
#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
#ifndef __ASSEMBLY__
static inline pte_t pte_wrprotect(pte_t pte)
{
return __pte(pte_val(pte) & ~(_PAGE_RW | _PAGE_HWWRITE));
}
#define pte_wrprotect pte_wrprotect
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~(_PAGE_DIRTY | _PAGE_HWWRITE));
}
#define pte_mkclean pte_mkclean
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_NOHASH_32_PTE_40x_H */
arch/powerpc/include/asm/nohash/pgtable.h
View file @ 2c74e258
......@@ -130,12 +130,10 @@ static inline pte_t pte_exprotect(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_EXEC);
}
#ifndef pte_mkclean
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~_PAGE_DIRTY);
}
#endif
static inline pte_t pte_mkold(pte_t pte)
{
......
arch/powerpc/kernel/head_40x.S
View file @ 2c74e258
......@@ -176,135 +176,16 @@ _ENTRY(saved_ksp_limit)
* 0x0300 - Data Storage Exception
* This happens for just a few reasons. U0 set (but we don't do that),
* or zone protection fault (user violation, write to protected page).
* If this is just an update of modified status, we do that quickly
* and exit. Otherwise, we call heavywight functions to do the work.
* The other Data TLB exceptions bail out to this point
* if they can't resolve the lightweight TLB fault.
*/
START_EXCEPTION(0x0300, DataStorage)
mtspr SPRN_SPRG_SCRATCH0, r10 /* Save some working registers */
mtspr SPRN_SPRG_SCRATCH1, r11
#ifdef CONFIG_403GCX
stw r12, 0(r0)
stw r9, 4(r0)
mfcr r11
mfspr r12, SPRN_PID
stw r11, 8(r0)
stw r12, 12(r0)
#else
mtspr SPRN_SPRG_SCRATCH3, r12
mtspr SPRN_SPRG_SCRATCH4, r9
mfcr r11
mfspr r12, SPRN_PID
mtspr SPRN_SPRG_SCRATCH6, r11
mtspr SPRN_SPRG_SCRATCH5, r12
#endif
/* First, check if it was a zone fault (which means a user
* tried to access a kernel or read-protected page - always
* a SEGV). All other faults here must be stores, so no
* need to check ESR_DST as well. */
mfspr r10, SPRN_ESR
andis. r10, r10, ESR_DIZ@h
bne 2f
mfspr r10, SPRN_DEAR /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11, PAGE_OFFSET@h
cmplw r10, r11
blt+ 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
li r9, 0
mtspr SPRN_PID, r9 /* TLB will have 0 TID */
b 4f
/* Get the PGD for the current thread.
*/
3:
mfspr r11,SPRN_SPRG_THREAD
lwz r11,PGDIR(r11)
4:
tophys(r11, r11)
rlwimi r11, r10, 12, 20, 29 /* Create L1 (pgdir/pmd) address */
lwz r11, 0(r11) /* Get L1 entry */
rlwinm. r12, r11, 0, 0, 19 /* Extract L2 (pte) base address */
beq 2f /* Bail if no table */
rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
lwz r11, 0(r12) /* Get Linux PTE */
andi. r9, r11, _PAGE_RW /* Is it writeable? */
beq 2f /* Bail if not */
/* Update 'changed'.
*/
ori r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
stw r11, 0(r12) /* Update Linux page table */
/* Most of the Linux PTE is ready to load into the TLB LO.
* We set ZSEL, where only the LS-bit determines user access.
* We set execute, because we don't have the granularity to
* properly set this at the page level (Linux problem).
* If shared is set, we cause a zero PID->TID load.
* Many of these bits are software only. Bits we don't set
* here we (properly should) assume have the appropriate value.
*/
li r12, 0x0ce2
andc r11, r11, r12 /* Make sure 20, 21 are zero */
/* find the TLB index that caused the fault. It has to be here.
*/
tlbsx r9, 0, r10
tlbwe r11, r9, TLB_DATA /* Load TLB LO */
/* Done...restore registers and get out of here.
*/
#ifdef CONFIG_403GCX
lwz r12, 12(r0)
lwz r11, 8(r0)
mtspr SPRN_PID, r12
mtcr r11
lwz r9, 4(r0)
lwz r12, 0(r0)
#else
mfspr r12, SPRN_SPRG_SCRATCH5
mfspr r11, SPRN_SPRG_SCRATCH6
mtspr SPRN_PID, r12
mtcr r11
mfspr r9, SPRN_SPRG_SCRATCH4
mfspr r12, SPRN_SPRG_SCRATCH3
#endif
mfspr r11, SPRN_SPRG_SCRATCH1
mfspr r10, SPRN_SPRG_SCRATCH0
PPC405_ERR77_SYNC
rfi /* Should sync shadow TLBs */
b . /* prevent prefetch past rfi */
2:
/* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
#ifdef CONFIG_403GCX
lwz r12, 12(r0)
lwz r11, 8(r0)
mtspr SPRN_PID, r12
mtcr r11
lwz r9, 4(r0)
lwz r12, 0(r0)
#else
mfspr r12, SPRN_SPRG_SCRATCH5
mfspr r11, SPRN_SPRG_SCRATCH6
mtspr SPRN_PID, r12
mtcr r11
mfspr r9, SPRN_SPRG_SCRATCH4
mfspr r12, SPRN_SPRG_SCRATCH3
#endif
mfspr r11, SPRN_SPRG_SCRATCH1
mfspr r10, SPRN_SPRG_SCRATCH0
b DataAccess
EXCEPTION_PROLOG
mfspr r5, SPRN_ESR /* Grab the ESR, save it, pass arg3 */
stw r5, _ESR(r11)
mfspr r4, SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */
stw r4, _DEAR(r11)
EXC_XFER_LITE(0x300, handle_page_fault)
/*
* 0x0400 - Instruction Storage Exception
......@@ -415,11 +296,17 @@ _ENTRY(saved_ksp_limit)
rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
lwz r11, 0(r12) /* Get Linux PTE */
andi. r9, r11, _PAGE_PRESENT
beq 5f
#ifdef CONFIG_SWAP
li r9, _PAGE_PRESENT | _PAGE_ACCESSED
#else
li r9, _PAGE_PRESENT
#endif
andc. r9, r9, r11 /* Check permission */
bne 5f
ori r11, r11, _PAGE_ACCESSED
stw r11, 0(r12)
rlwinm r9, r11, 1, _PAGE_RW /* dirty => rw */
and r9, r9, r11 /* hwwrite = dirty & rw */
rlwimi r11, r9, 0, _PAGE_RW /* replace rw by hwwrite */
/* Create TLB tag. This is the faulting address plus a static
* set of bits. These are size, valid, E, U0.
......@@ -463,7 +350,7 @@ _ENTRY(saved_ksp_limit)
#endif
mfspr r11, SPRN_SPRG_SCRATCH1
mfspr r10, SPRN_SPRG_SCRATCH0
b DataAccess
b DataStorage
/* 0x1200 - Instruction TLB Miss Exception
* Nearly the same as above, except we get our information from different
......@@ -515,11 +402,17 @@ _ENTRY(saved_ksp_limit)
rlwimi r12, r10, 22, 20, 29 /* Compute PTE address */
lwz r11, 0(r12) /* Get Linux PTE */
andi. r9, r11, _PAGE_PRESENT
beq 5f
#ifdef CONFIG_SWAP
li r9, _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
#else
li r9, _PAGE_PRESENT | _PAGE_EXEC
#endif
andc. r9, r9, r11 /* Check permission */
bne 5f
ori r11, r11, _PAGE_ACCESSED
stw r11, 0(r12)
rlwinm r9, r11, 1, _PAGE_RW /* dirty => rw */
and r9, r9, r11 /* hwwrite = dirty & rw */
rlwimi r11, r9, 0, _PAGE_RW /* replace rw by hwwrite */
/* Create TLB tag. This is the faulting address plus a static
* set of bits. These are size, valid, E, U0.
......@@ -669,18 +562,6 @@ WDTException:
(MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)),
crit_transfer_to_handler, ret_from_crit_exc)
/*
* The other Data TLB exceptions bail out to this point
* if they can't resolve the lightweight TLB fault.
*/
DataAccess:
EXCEPTION_PROLOG
mfspr r5,SPRN_ESR /* Grab the ESR, save it, pass arg3 */
stw r5,_ESR(r11)
mfspr r4,SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */
stw r4, _DEAR(r11)
EXC_XFER_LITE(0x300, handle_page_fault)
/* Other PowerPC processors, namely those derived from the 6xx-series
* have vectors from 0x2100 through 0x2F00 defined, but marked as reserved.
* However, for the 4xx-series processors these are neither defined nor
......
arch/powerpc/mm/nohash/40x.c
View file @ 2c74e258
......@@ -102,7 +102,7 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
while (s >= LARGE_PAGE_SIZE_16M) {
pmd_t *pmdp;
unsigned long val = p | _PMD_SIZE_16M | _PAGE_EXEC | _PAGE_HWWRITE;
unsigned long val = p | _PMD_SIZE_16M | _PAGE_EXEC | _PAGE_RW;
pmdp = pmd_ptr_k(v);
*pmdp++ = __pmd(val);
......@@ -117,7 +117,7 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
while (s >= LARGE_PAGE_SIZE_4M) {
pmd_t *pmdp;
unsigned long val = p | _PMD_SIZE_4M | _PAGE_EXEC | _PAGE_HWWRITE;
unsigned long val = p | _PMD_SIZE_4M | _PAGE_EXEC | _PAGE_RW;
pmdp = pmd_ptr_k(v);
*pmdp = __pmd(val);
......
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