From 316ec0624f951166daedbe446988ef92ae72b59f Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Sat, 11 Mar 2017 18:03:34 -0500 Subject: parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range The previously submitted patch did not resolve the random segmentation faults observed on the phantom buildd system. There are still unresolved problems with the Debian 4.8 and 4.9 kernels on C8000. The attached patch removes the flush of the offset map pages and does a whole data cache flush for large ranges. No other arch flushes the offset map in these routines as far as I can tell. I have not observed any random segmentation faults on rp3440 in two weeks of testing with 4.10.0 and 4.10.1. Signed-off-by: John David Anglin Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Helge Deller --- arch/parisc/include/asm/cacheflush.h | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) (limited to 'arch/parisc/include/asm') diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h index 19c9c3c5f267..c7e15cc5c668 100644 --- a/arch/parisc/include/asm/cacheflush.h +++ b/arch/parisc/include/asm/cacheflush.h @@ -43,28 +43,9 @@ static inline void flush_kernel_dcache_page(struct page *page) #define flush_kernel_dcache_range(start,size) \ flush_kernel_dcache_range_asm((start), (start)+(size)); -/* vmap range flushes and invalidates. Architecturally, we don't need - * the invalidate, because the CPU should refuse to speculate once an - * area has been flushed, so invalidate is left empty */ -static inline void flush_kernel_vmap_range(void *vaddr, int size) -{ - unsigned long start = (unsigned long)vaddr; - - flush_kernel_dcache_range_asm(start, start + size); -} -static inline void invalidate_kernel_vmap_range(void *vaddr, int size) -{ - unsigned long start = (unsigned long)vaddr; - void *cursor = vaddr; - for ( ; cursor < vaddr + size; cursor += PAGE_SIZE) { - struct page *page = vmalloc_to_page(cursor); - - if (test_and_clear_bit(PG_dcache_dirty, &page->flags)) - flush_kernel_dcache_page(page); - } - flush_kernel_dcache_range_asm(start, start + size); -} +void flush_kernel_vmap_range(void *vaddr, int size); +void invalidate_kernel_vmap_range(void *vaddr, int size); #define flush_cache_vmap(start, end) flush_cache_all() #define flush_cache_vunmap(start, end) flush_cache_all() -- cgit v1.2.3 From 186ecf14e58befba434f0774eea89e35f64d3c6a Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Wed, 15 Mar 2017 21:48:42 +0100 Subject: parisc: Avoid compiler warnings with access_ok() Commit 09b871ffd4d8 (parisc: Define access_ok() as macro) missed to mark uaddr as used, which then gives compiler warnings about unused variables. Fix it by comparing uaddr to uaddr which then gets optimized away by the compiler. Signed-off-by: Helge Deller Fixes: 09b871ffd4d8 ("parisc: Define access_ok() as macro") --- arch/parisc/include/asm/uaccess.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/parisc/include/asm') diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index fb4382c28259..edfbf9d6a6dd 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -32,7 +32,8 @@ * that put_user is the same as __put_user, etc. */ -#define access_ok(type, uaddr, size) (1) +#define access_ok(type, uaddr, size) \ + ( (uaddr) == (uaddr) ) #define put_user __put_user #define get_user __get_user -- cgit v1.2.3 From d19f5e41b344a057bb2450024a807476f30978d2 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 25 Mar 2017 11:59:15 +0100 Subject: parisc: Clean up fixup routines for get_user()/put_user() Al Viro noticed that userspace accesses via get_user()/put_user() can be simplified a lot with regard to usage of the exception handling. This patch implements a fixup routine for get_user() and put_user() in such that the exception handler will automatically load -EFAULT into the register %r8 (the error value) in case on a fault on userspace. Additionally the fixup routine will zero the target register on fault in case of a get_user() call. The target register is extracted out of the faulting assembly instruction. This patch brings a few benefits over the old implementation: 1. Exception handling gets much cleaner, easier and smaller in size. 2. Helper functions like fixup_get_user_skip_1 (all of fixup.S) can be dropped. 3. No need to hardcode %r9 as target register for get_user() any longer. This helps the compiler register allocator and thus creates less assembler statements. 4. No dependency on the exception_data contents any longer. 5. Nested faults will be handled cleanly. Reported-by: Al Viro Cc: # v4.9+ Signed-off-by: Helge Deller --- arch/parisc/include/asm/uaccess.h | 59 +++++++++++++---------- arch/parisc/kernel/parisc_ksyms.c | 10 ---- arch/parisc/lib/Makefile | 2 +- arch/parisc/lib/fixup.S | 98 --------------------------------------- arch/parisc/mm/fault.c | 17 +++++++ 5 files changed, 52 insertions(+), 134 deletions(-) delete mode 100644 arch/parisc/lib/fixup.S (limited to 'arch/parisc/include/asm') diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index edfbf9d6a6dd..8442727f28d2 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -64,6 +64,15 @@ struct exception_table_entry { ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \ ".previous\n" +/* + * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry + * (with lowest bit set) for which the fault handler in fixup_exception() will + * load -EFAULT into %r8 for a read or write fault, and zeroes the target + * register in case of a read fault in get_user(). + */ +#define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\ + ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1) + /* * The page fault handler stores, in a per-cpu area, the following information * if a fixup routine is available. @@ -91,7 +100,7 @@ struct exception_data { #define __get_user(x, ptr) \ ({ \ register long __gu_err __asm__ ("r8") = 0; \ - register long __gu_val __asm__ ("r9") = 0; \ + register long __gu_val; \ \ load_sr2(); \ switch (sizeof(*(ptr))) { \ @@ -107,22 +116,23 @@ struct exception_data { }) #define __get_user_asm(ldx, ptr) \ - __asm__("\n1:\t" ldx "\t0(%%sr2,%2),%0\n\t" \ - ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\ + __asm__("1: " ldx " 0(%%sr2,%2),%0\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ : "=r"(__gu_val), "=r"(__gu_err) \ - : "r"(ptr), "1"(__gu_err) \ - : "r1"); + : "r"(ptr), "1"(__gu_err)); #if !defined(CONFIG_64BIT) #define __get_user_asm64(ptr) \ - __asm__("\n1:\tldw 0(%%sr2,%2),%0" \ - "\n2:\tldw 4(%%sr2,%2),%R0\n\t" \ - ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_2)\ - ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_get_user_skip_1)\ + __asm__(" copy %%r0,%R0\n" \ + "1: ldw 0(%%sr2,%2),%0\n" \ + "2: ldw 4(%%sr2,%2),%R0\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \ : "=r"(__gu_val), "=r"(__gu_err) \ - : "r"(ptr), "1"(__gu_err) \ - : "r1"); + : "r"(ptr), "1"(__gu_err)); #endif /* !defined(CONFIG_64BIT) */ @@ -148,32 +158,31 @@ struct exception_data { * The "__put_user/kernel_asm()" macros tell gcc they read from memory * instead of writing. This is because they do not write to any memory * gcc knows about, so there are no aliasing issues. These macros must - * also be aware that "fixup_put_user_skip_[12]" are executed in the - * context of the fault, and any registers used there must be listed - * as clobbers. In this case only "r1" is used by the current routines. - * r8/r9 are already listed as err/val. + * also be aware that fixups are executed in the context of the fault, + * and any registers used there must be listed as clobbers. + * r8 is already listed as err. */ #define __put_user_asm(stx, x, ptr) \ __asm__ __volatile__ ( \ - "\n1:\t" stx "\t%2,0(%%sr2,%1)\n\t" \ - ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\ + "1: " stx " %2,0(%%sr2,%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ : "=r"(__pu_err) \ - : "r"(ptr), "r"(x), "0"(__pu_err) \ - : "r1") + : "r"(ptr), "r"(x), "0"(__pu_err)) #if !defined(CONFIG_64BIT) #define __put_user_asm64(__val, ptr) do { \ __asm__ __volatile__ ( \ - "\n1:\tstw %2,0(%%sr2,%1)" \ - "\n2:\tstw %R2,4(%%sr2,%1)\n\t" \ - ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\ - ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\ + "1: stw %2,0(%%sr2,%1)\n" \ + "2: stw %R2,4(%%sr2,%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \ : "=r"(__pu_err) \ - : "r"(ptr), "r"(__val), "0"(__pu_err) \ - : "r1"); \ + : "r"(ptr), "r"(__val), "0"(__pu_err)); \ } while (0) #endif /* !defined(CONFIG_64BIT) */ diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c index 7484b3d11e0d..c6d6272a934f 100644 --- a/arch/parisc/kernel/parisc_ksyms.c +++ b/arch/parisc/kernel/parisc_ksyms.c @@ -47,16 +47,6 @@ EXPORT_SYMBOL(__cmpxchg_u64); EXPORT_SYMBOL(lclear_user); EXPORT_SYMBOL(lstrnlen_user); -/* Global fixups - defined as int to avoid creation of function pointers */ -extern int fixup_get_user_skip_1; -extern int fixup_get_user_skip_2; -extern int fixup_put_user_skip_1; -extern int fixup_put_user_skip_2; -EXPORT_SYMBOL(fixup_get_user_skip_1); -EXPORT_SYMBOL(fixup_get_user_skip_2); -EXPORT_SYMBOL(fixup_put_user_skip_1); -EXPORT_SYMBOL(fixup_put_user_skip_2); - #ifndef CONFIG_64BIT /* Needed so insmod can set dp value */ extern int $global$; diff --git a/arch/parisc/lib/Makefile b/arch/parisc/lib/Makefile index 8fa92b8d839a..f2dac4d73b1b 100644 --- a/arch/parisc/lib/Makefile +++ b/arch/parisc/lib/Makefile @@ -2,7 +2,7 @@ # Makefile for parisc-specific library files # -lib-y := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o \ +lib-y := lusercopy.o bitops.o checksum.o io.o memset.o memcpy.o \ ucmpdi2.o delay.o obj-y := iomap.o diff --git a/arch/parisc/lib/fixup.S b/arch/parisc/lib/fixup.S deleted file mode 100644 index a5b72f22c7a6..000000000000 --- a/arch/parisc/lib/fixup.S +++ /dev/null @@ -1,98 +0,0 @@ -/* - * Linux/PA-RISC Project (http://www.parisc-linux.org/) - * - * Copyright (C) 2004 Randolph Chung - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2, or (at your option) - * any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - * - * Fixup routines for kernel exception handling. - */ -#include -#include -#include -#include - -#ifdef CONFIG_SMP - .macro get_fault_ip t1 t2 - loadgp - addil LT%__per_cpu_offset,%r27 - LDREG RT%__per_cpu_offset(%r1),\t1 - /* t2 = smp_processor_id() */ - mfctl 30,\t2 - ldw TI_CPU(\t2),\t2 -#ifdef CONFIG_64BIT - extrd,u \t2,63,32,\t2 -#endif - /* t2 = &__per_cpu_offset[smp_processor_id()]; */ - LDREGX \t2(\t1),\t2 - addil LT%exception_data,%r27 - LDREG RT%exception_data(%r1),\t1 - /* t1 = this_cpu_ptr(&exception_data) */ - add,l \t1,\t2,\t1 - /* %r27 = t1->fault_gp - restore gp */ - LDREG EXCDATA_GP(\t1), %r27 - /* t1 = t1->fault_ip */ - LDREG EXCDATA_IP(\t1), \t1 - .endm -#else - .macro get_fault_ip t1 t2 - loadgp - /* t1 = this_cpu_ptr(&exception_data) */ - addil LT%exception_data,%r27 - LDREG RT%exception_data(%r1),\t2 - /* %r27 = t2->fault_gp - restore gp */ - LDREG EXCDATA_GP(\t2), %r27 - /* t1 = t2->fault_ip */ - LDREG EXCDATA_IP(\t2), \t1 - .endm -#endif - - .level LEVEL - - .text - .section .fixup, "ax" - - /* get_user() fixups, store -EFAULT in r8, and 0 in r9 */ -ENTRY_CFI(fixup_get_user_skip_1) - get_fault_ip %r1,%r8 - ldo 4(%r1), %r1 - ldi -EFAULT, %r8 - bv %r0(%r1) - copy %r0, %r9 -ENDPROC_CFI(fixup_get_user_skip_1) - -ENTRY_CFI(fixup_get_user_skip_2) - get_fault_ip %r1,%r8 - ldo 8(%r1), %r1 - ldi -EFAULT, %r8 - bv %r0(%r1) - copy %r0, %r9 -ENDPROC_CFI(fixup_get_user_skip_2) - - /* put_user() fixups, store -EFAULT in r8 */ -ENTRY_CFI(fixup_put_user_skip_1) - get_fault_ip %r1,%r8 - ldo 4(%r1), %r1 - bv %r0(%r1) - ldi -EFAULT, %r8 -ENDPROC_CFI(fixup_put_user_skip_1) - -ENTRY_CFI(fixup_put_user_skip_2) - get_fault_ip %r1,%r8 - ldo 8(%r1), %r1 - bv %r0(%r1) - ldi -EFAULT, %r8 -ENDPROC_CFI(fixup_put_user_skip_2) - diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index deab89a8915a..32ec22146141 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -150,6 +150,23 @@ int fixup_exception(struct pt_regs *regs) d->fault_space = regs->isr; d->fault_addr = regs->ior; + /* + * Fix up get_user() and put_user(). + * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant + * bit in the relative address of the fixup routine to indicate + * that %r8 should be loaded with -EFAULT to report a userspace + * access error. + */ + if (fix->fixup & 1) { + regs->gr[8] = -EFAULT; + + /* zero target register for get_user() */ + if (parisc_acctyp(0, regs->iir) == VM_READ) { + int treg = regs->iir & 0x1f; + regs->gr[treg] = 0; + } + } + regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup; regs->iaoq[0] &= ~3; /* -- cgit v1.2.3