From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 28 May 2012 13:03:47 +1000 From: Paul Mackerras To: Linus Torvalds Subject: [PATCH 2/2] powerpc: Use the new generic strncpy_from_user() and strnlen_user() Message-ID: <20120528030347.GB6822@bloggs.ozlabs.ibm.com> References: <20120528025956.GA6822@bloggs.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20120528025956.GA6822@bloggs.ozlabs.ibm.com> Cc: linuxppc-dev@ozlabs.org, David Miller List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is much the same as for SPARC except that we can do the find_zero() function more efficiently using the count-leading-zeroes instructions. Tested on 32-bit and 64-bit PowerPC. Signed-off-by: Paul Mackerras --- I'm sending this in without Ben H's ack as he is away for a few weeks for medical reasons. arch/powerpc/Kconfig | 2 ++ arch/powerpc/include/asm/uaccess.h | 41 ++++---------------------- arch/powerpc/include/asm/word-at-a-time.h | 41 ++++++++++++++++++++++++++ arch/powerpc/kernel/ppc_ksyms.c | 2 -- arch/powerpc/lib/string.S | 45 ----------------------------- 5 files changed, 48 insertions(+), 83 deletions(-) create mode 100644 arch/powerpc/include/asm/word-at-a-time.h diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 00b9874..050cb37 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -135,6 +135,8 @@ config PPC select GENERIC_CMOS_UPDATE select GENERIC_TIME_VSYSCALL select GENERIC_CLOCKEVENTS + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER config EARLY_PRINTK bool diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index bd0fb84..17bb40c 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -40,6 +40,8 @@ #define segment_eq(a, b) ((a).seg == (b).seg) +#define user_addr_max() (get_fs().seg) + #ifdef __powerpc64__ /* * This check is sufficient because there is a large enough @@ -453,42 +455,9 @@ static inline unsigned long clear_user(void __user *addr, unsigned long size) return size; } -extern int __strncpy_from_user(char *dst, const char __user *src, long count); - -static inline long strncpy_from_user(char *dst, const char __user *src, - long count) -{ - might_sleep(); - if (likely(access_ok(VERIFY_READ, src, 1))) - return __strncpy_from_user(dst, src, count); - return -EFAULT; -} - -/* - * Return the size of a string (including the ending 0) - * - * Return 0 for error - */ -extern int __strnlen_user(const char __user *str, long len, unsigned long top); - -/* - * Returns the length of the string at str (including the null byte), - * or 0 if we hit a page we can't access, - * or something > len if we didn't find a null byte. - * - * The `top' parameter to __strnlen_user is to make sure that - * we can never overflow from the user area into kernel space. - */ -static inline int strnlen_user(const char __user *str, long len) -{ - unsigned long top = current->thread.fs.seg; - - if ((unsigned long)str > top) - return 0; - return __strnlen_user(str, len, top); -} - -#define strlen_user(str) strnlen_user((str), 0x7ffffffe) +extern long strncpy_from_user(char *dst, const char __user *src, long count); +extern __must_check long strlen_user(const char __user *str); +extern __must_check long strnlen_user(const char __user *str, long n); #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/include/asm/word-at-a-time.h b/arch/powerpc/include/asm/word-at-a-time.h new file mode 100644 index 0000000..d0b6d4a --- /dev/null +++ b/arch/powerpc/include/asm/word-at-a-time.h @@ -0,0 +1,41 @@ +#ifndef _ASM_WORD_AT_A_TIME_H +#define _ASM_WORD_AT_A_TIME_H + +/* + * Word-at-a-time interfaces for PowerPC. + */ + +#include +#include + +struct word_at_a_time { + const unsigned long high_bits, low_bits; +}; + +#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) } + +/* Bit set in the bytes that have a zero */ +static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c) +{ + unsigned long mask = (val & c->low_bits) + c->low_bits; + return ~(mask | rhs); +} + +#define create_zero_mask(mask) (mask) + +static inline long find_zero(unsigned long mask) +{ + long leading_zero_bits; + + asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask)); + return leading_zero_bits >> 3; +} + +static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) +{ + unsigned long rhs = val | c->low_bits; + *data = rhs; + return (val + c->high_bits) & ~rhs; +} + +#endif /* _ASM_WORD_AT_A_TIME_H */ diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c index d1f2aaf..3e40315 100644 --- a/arch/powerpc/kernel/ppc_ksyms.c +++ b/arch/powerpc/kernel/ppc_ksyms.c @@ -85,8 +85,6 @@ EXPORT_SYMBOL(csum_tcpudp_magic); EXPORT_SYMBOL(__copy_tofrom_user); EXPORT_SYMBOL(__clear_user); -EXPORT_SYMBOL(__strncpy_from_user); -EXPORT_SYMBOL(__strnlen_user); EXPORT_SYMBOL(copy_page); #if defined(CONFIG_PCI) && defined(CONFIG_PPC32) diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S index 455881a..093d631 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -160,48 +160,3 @@ _GLOBAL(__clear_user) PPC_LONG 1b,91b PPC_LONG 8b,92b .text - -_GLOBAL(__strncpy_from_user) - addi r6,r3,-1 - addi r4,r4,-1 - cmpwi 0,r5,0 - beq 2f - mtctr r5 -1: lbzu r0,1(r4) - cmpwi 0,r0,0 - stbu r0,1(r6) - bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */ - beq 3f -2: addi r6,r6,1 -3: subf r3,r3,r6 - blr -99: li r3,-EFAULT - blr - - .section __ex_table,"a" - PPC_LONG 1b,99b - .text - -/* r3 = str, r4 = len (> 0), r5 = top (highest addr) */ -_GLOBAL(__strnlen_user) - addi r7,r3,-1 - subf r6,r7,r5 /* top+1 - str */ - cmplw 0,r4,r6 - bge 0f - mr r6,r4 -0: mtctr r6 /* ctr = min(len, top - str) */ -1: lbzu r0,1(r7) /* get next byte */ - cmpwi 0,r0,0 - bdnzf 2,1b /* loop if --ctr != 0 && byte != 0 */ - addi r7,r7,1 - subf r3,r3,r7 /* number of bytes we have looked at */ - beqlr /* return if we found a 0 byte */ - cmpw 0,r3,r4 /* did we look at all len bytes? */ - blt 99f /* if not, must have hit top */ - addi r3,r4,1 /* return len + 1 to indicate no null found */ - blr -99: li r3,0 /* bad address, return 0 */ - blr - - .section __ex_table,"a" - PPC_LONG 1b,99b -- 1.7.10.rc3.219.g53414