[POWERPC] 4xx: Fix 4xx flush_tlb_page()

On 4xx CPUs, the current implementation of flush_tlb_page() uses
a low level _tlbie() assembly function that only works for the
current PID. Thus, invalidations caused by, for example, a COW
fault triggered by get_user_pages() from a different context will
not work properly, causing among other things, gdb breakpoints
to fail.

This patch adds a "pid" argument to _tlbie() on 4xx processors,
and uses it to flush entries in the right context. FSL BookE
also gets the argument but it seems they don't need it (their
tlbivax form ignores the PID when invalidating according to the
document I have).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

arch/powerpc/kernel/misc_32.S

@@ -288,7 +288,16 @@ _GLOBAL(_tlbia)
  */
 _GLOBAL(_tlbie)
 #if defined(CONFIG_40x)
+	/* We run the search with interrupts disabled because we have to change
+	 * the PID and I don't want to preempt when that happens.
+	 */
+	mfmsr	r5
+	mfspr	r6,SPRN_PID
+	wrteei	0
+	mtspr	SPRN_PID,r4
 	tlbsx.	r3, 0, r3
+	mtspr	SPRN_PID,r6
+	wrtee	r5
 	bne	10f
 	sync
 	/* There are only 64 TLB entries, so r3 < 64, which means bit 25 is clear.
@@ -297,23 +306,23 @@ _GLOBAL(_tlbie)
 	tlbwe	r3, r3, TLB_TAG
 	isync
 10:
+
 #elif defined(CONFIG_44x)
-	mfspr	r4,SPRN_MMUCR
-	mfspr	r5,SPRN_PID			/* Get PID */
-	rlwimi	r4,r5,0,24,31			/* Set TID */
+	mfspr	r5,SPRN_MMUCR
+	rlwimi	r5,r4,0,24,31			/* Set TID */
 
 	/* We have to run the search with interrupts disabled, even critical
 	 * and debug interrupts (in fact the only critical exceptions we have
 	 * are debug and machine check).  Otherwise  an interrupt which causes
 	 * a TLB miss can clobber the MMUCR between the mtspr and the tlbsx. */
-	mfmsr	r5
+	mfmsr	r4
 	lis	r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@ha
 	addi	r6,r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@l
-	andc	r6,r5,r6
+	andc	r6,r4,r6
 	mtmsr	r6
-	mtspr	SPRN_MMUCR,r4
+	mtspr	SPRN_MMUCR,r5
 	tlbsx.	r3, 0, r3
-	mtmsr	r5
+	mtmsr	r4
 	bne	10f
 	sync
 	/* There are only 64 TLB entries, so r3 < 64,

arch/powerpc/mm/fault.c

@@ -309,7 +309,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 					set_bit(PG_arch_1, &page->flags);
 				}
 				pte_update(ptep, 0, _PAGE_HWEXEC);
-				_tlbie(address);
+				_tlbie(address, mm->context.id);
 				pte_unmap_unlock(ptep, ptl);
 				up_read(&mm->mmap_sem);
 				return 0;

arch/powerpc/mm/mmu_decl.h

@@ -61,12 +61,12 @@ extern unsigned long total_lowmem;
 #define mmu_mapin_ram()		(0UL)
 
 #elif defined(CONFIG_4xx)
-#define flush_HPTE(X, va, pg)	_tlbie(va)
+#define flush_HPTE(pid, va, pg)	_tlbie(va, pid)
 extern void MMU_init_hw(void);
 extern unsigned long mmu_mapin_ram(void);
 
 #elif defined(CONFIG_FSL_BOOKE)
-#define flush_HPTE(X, va, pg)	_tlbie(va)
+#define flush_HPTE(pid, va, pg)	_tlbie(va, pid)
 extern void MMU_init_hw(void);
 extern unsigned long mmu_mapin_ram(void);
 extern void adjust_total_lowmem(void);

arch/ppc/kernel/misc.S

@@ -224,7 +224,16 @@ _GLOBAL(_tlbia)
  */
 _GLOBAL(_tlbie)
 #if defined(CONFIG_40x)
+	/* We run the search with interrupts disabled because we have to change
+	 * the PID and I don't want to preempt when that happens.
+	 */
+	mfmsr	r5
+	mfspr	r6,SPRN_PID
+	wrteei	0
+	mtspr	SPRN_PID,r4
 	tlbsx.	r3, 0, r3
+	mtspr	SPRN_PID,r6
+	wrtee	r5
 	bne	10f
 	sync
 	/* There are only 64 TLB entries, so r3 < 64, which means bit 25 is clear.
@@ -234,22 +243,21 @@ _GLOBAL(_tlbie)
 	isync
 10:
 #elif defined(CONFIG_44x)
-	mfspr	r4,SPRN_MMUCR
-	mfspr	r5,SPRN_PID			/* Get PID */
-	rlwimi	r4,r5,0,24,31			/* Set TID */
+	mfspr	r5,SPRN_MMUCR
+	rlwimi	r5,r4,0,24,31			/* Set TID */
 
 	/* We have to run the search with interrupts disabled, even critical
 	 * and debug interrupts (in fact the only critical exceptions we have
 	 * are debug and machine check).  Otherwise  an interrupt which causes
 	 * a TLB miss can clobber the MMUCR between the mtspr and the tlbsx. */
-	mfmsr	r5
+	mfmsr	r4
 	lis	r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@ha
 	addi	r6,r6,(MSR_EE|MSR_CE|MSR_ME|MSR_DE)@l
-	andc	r6,r5,r6
+	andc	r6,r4,r6
 	mtmsr	r6
-	mtspr	SPRN_MMUCR,r4
+	mtspr	SPRN_MMUCR,r5
 	tlbsx.	r3, 0, r3
-	mtmsr	r5
+	mtmsr	r4
 	bne	10f
 	sync
 	/* There are only 64 TLB entries, so r3 < 64,

arch/ppc/mm/fault.c

@@ -227,7 +227,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 					set_bit(PG_arch_1, &page->flags);
 				}
 				pte_update(ptep, 0, _PAGE_HWEXEC);
-				_tlbie(address);
+				_tlbie(address, mm->context.id);
 				pte_unmap_unlock(ptep, ptl);
 				up_read(&mm->mmap_sem);
 				return 0;

arch/ppc/mm/mmu_decl.h

@@ -54,12 +54,12 @@ extern unsigned int num_tlbcam_entries;
 #define mmu_mapin_ram()		(0UL)
 
 #elif defined(CONFIG_4xx)
-#define flush_HPTE(X, va, pg)	_tlbie(va)
+#define flush_HPTE(pid, va, pg)	_tlbie(va, pid)
 extern void MMU_init_hw(void);
 extern unsigned long mmu_mapin_ram(void);
 
 #elif defined(CONFIG_FSL_BOOKE)
-#define flush_HPTE(X, va, pg)	_tlbie(va)
+#define flush_HPTE(pid, va, pg)	_tlbie(va, pid)
 extern void MMU_init_hw(void);
 extern unsigned long mmu_mapin_ram(void);
 extern void adjust_total_lowmem(void);

arch/ppc/platforms/4xx/ebony.c

@@ -236,7 +236,7 @@ ebony_early_serial_map(void)
 	gen550_init(0, &port);
 
 	/* Purge TLB entry added in head_44x.S for early serial access */
-	_tlbie(UART0_IO_BASE);
+	_tlbie(UART0_IO_BASE, 0);
 #endif
 
 	port.membase = ioremap64(PPC440GP_UART1_ADDR, 8);

arch/ppc/platforms/4xx/ocotea.c

@@ -259,7 +259,7 @@ ocotea_early_serial_map(void)
 	gen550_init(0, &port);
 
 	/* Purge TLB entry added in head_44x.S for early serial access */
-	_tlbie(UART0_IO_BASE);
+	_tlbie(UART0_IO_BASE, 0);
 #endif
 
 	port.membase = ioremap64(PPC440GX_UART1_ADDR, 8);

arch/ppc/platforms/4xx/taishan.c

@@ -316,7 +316,7 @@ taishan_early_serial_map(void)
 	gen550_init(0, &port);
 
 	/* Purge TLB entry added in head_44x.S for early serial access */
-	_tlbie(UART0_IO_BASE);
+	_tlbie(UART0_IO_BASE, 0);
 #endif
 
 	port.membase = ioremap64(PPC440GX_UART1_ADDR, 8);

include/asm-powerpc/tlbflush.h

 #ifndef _ASM_POWERPC_TLBFLUSH_H
 #define _ASM_POWERPC_TLBFLUSH_H
+
 /*
  * TLB flushing:
  *
@@ -16,9 +17,6 @@
  */
 #ifdef __KERNEL__
 
-struct mm_struct;
-struct vm_area_struct;
-
 #if defined(CONFIG_4xx) || defined(CONFIG_8xx) || defined(CONFIG_FSL_BOOKE)
 /*
  * TLB flushing for software loaded TLB chips
@@ -28,7 +26,9 @@ struct vm_area_struct;
  * specific tlbie's
  */
 
-extern void _tlbie(unsigned long address);
+#include <linux/mm.h>
+
+extern void _tlbie(unsigned long address, unsigned int pid);
 
 #if defined(CONFIG_40x) || defined(CONFIG_8xx)
 #define _tlbia()	asm volatile ("tlbia; sync" : : : "memory")
@@ -44,13 +44,13 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
 static inline void flush_tlb_page(struct vm_area_struct *vma,
 				  unsigned long vmaddr)
 {
-	_tlbie(vmaddr);
+	_tlbie(vmaddr, vma->vm_mm->context.id);
 }
 
 static inline void flush_tlb_page_nohash(struct vm_area_struct *vma,
 					 unsigned long vmaddr)
 {
-	_tlbie(vmaddr);
+	_tlbie(vmaddr, vma->vm_mm->context.id);
 }
 
 static inline void flush_tlb_range(struct vm_area_struct *vma,