| Message ID | 20210908204405.127665-1-deller@gmx.de (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [1/4] parisc: Drop strnlen_user() in favour of generic version | expand |
On Wed, Sep 8, 2021 at 10:44 PM Helge Deller <deller@gmx.de> wrote: > > As suggested by Arnd Bergmann, drop the parisc version of > strnlen_user() and switch to the generic version. The strnlen_user() removal looks good, Acked-by: Arnd Bergmann <arnd@arndb.de> > user_addr_max() was wrong too, fix it by using TASK_SIZE. Not sure about this part though: > /* > * Complex access routines -- macros > */ > -#define user_addr_max() (~0UL) > +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) We are getting very close to completely removing set_fs()/get_fs(), uaccess_kernel() and some related bits from the kernel, so I think it would be better to the other way here and finish off removing CONFIG_SET_FS from parisc. I think this will also simplify your asm/uaccess.h a lot, in particular since it has separate address spaces for __get_user() and __get_kernel_nofault(), and without set_fs() you can leave out the runtime conditional to switch between them. Arnd
On 9/8/21 11:26 PM, Arnd Bergmann wrote: > On Wed, Sep 8, 2021 at 10:44 PM Helge Deller <deller@gmx.de> wrote: >> >> As suggested by Arnd Bergmann, drop the parisc version of >> strnlen_user() and switch to the generic version. > > The strnlen_user() removal looks good, > > Acked-by: Arnd Bergmann <arnd@arndb.de> Good. >> user_addr_max() was wrong too, fix it by using TASK_SIZE. > > Not sure about this part though: > >> /* >> * Complex access routines -- macros >> */ >> -#define user_addr_max() (~0UL) >> +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) I noticed that our user_addr_max() was actually wrong. It's used in the generic strnlen_user() so fixing it seemed appropriate. > We are getting very close to completely removing set_fs()/get_fs(), > uaccess_kernel() and some related bits from the kernel, so I think > it would be better to the other way here and finish off removing > CONFIG_SET_FS from parisc. > > I think this will also simplify your asm/uaccess.h a lot, in particular > since it has separate address spaces for __get_user() and > __get_kernel_nofault(), and without set_fs() you can leave out > the runtime conditional to switch between them. That's a good idea and should probably be done. Do you have some pointers where to start, e.g. initial commits from other arches ? Helge
On Wed, Sep 8, 2021 at 11:40 PM Helge Deller <deller@gmx.de> wrote: > On 9/8/21 11:26 PM, Arnd Bergmann wrote: > >> /* > >> * Complex access routines -- macros > >> */ > >> -#define user_addr_max() (~0UL) > >> +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) > > I noticed that our user_addr_max() was actually wrong. > It's used in the generic strnlen_user() so fixing it seemed appropriate. The user_addr_max() definition should match what you do in access_ok() for USER_DS though, which is a nop on architectures that have split user address space, so I think the ~0UL was correct here. No matter what the arguments are, there is no danger of spilling over into kernel space, which is what the user_addr_max() check is trying to prevent on other architectures. > > We are getting very close to completely removing set_fs()/get_fs(), > > uaccess_kernel() and some related bits from the kernel, so I think > > it would be better to the other way here and finish off removing > > CONFIG_SET_FS from parisc. > > > > I think this will also simplify your asm/uaccess.h a lot, in particular > > since it has separate address spaces for __get_user() and > > __get_kernel_nofault(), and without set_fs() you can leave out > > the runtime conditional to switch between them. > > That's a good idea and should probably be done. > Do you have some pointers where to start, e.g. initial commits from other arches ? Russell just merged my series for arch/arm in linux-5.15, you can look at that but it's probably easier for parisc. I think the only part you need to add is __get_kernel_nofault() and __put_kernel_nofault(). You can see in mm/maccess.c what the difference between the two versions in there is. Once you have those, you define HAVE_GET_KERNEL_NOFAULT and then remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), thread_info->addr_limit, KERNEL_DS, and USER_DS. Arnd
* Arnd Bergmann <arnd@kernel.org>: > On Wed, Sep 8, 2021 at 11:40 PM Helge Deller <deller@gmx.de> wrote: > > On 9/8/21 11:26 PM, Arnd Bergmann wrote: > > >> /* > > >> * Complex access routines -- macros > > >> */ > > >> -#define user_addr_max() (~0UL) > > >> +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) > > > > I noticed that our user_addr_max() was actually wrong. > > It's used in the generic strnlen_user() so fixing it seemed appropriate. > > The user_addr_max() definition should match what you do in access_ok() > for USER_DS though, which is a nop on architectures that have split user > address space, so I think the ~0UL was correct here. > > No matter what the arguments are, there is no danger of spilling over > into kernel space, which is what the user_addr_max() check is trying > to prevent on other architectures. > > > > We are getting very close to completely removing set_fs()/get_fs(), > > > uaccess_kernel() and some related bits from the kernel, so I think > > > it would be better to the other way here and finish off removing > > > CONFIG_SET_FS from parisc. > > > > > > I think this will also simplify your asm/uaccess.h a lot, in particular > > > since it has separate address spaces for __get_user() and > > > __get_kernel_nofault(), and without set_fs() you can leave out > > > the runtime conditional to switch between them. > > > > That's a good idea and should probably be done. > > Do you have some pointers where to start, e.g. initial commits from other arches ? > > Russell just merged my series for arch/arm in linux-5.15, you > can look at that but it's probably easier for parisc. > > I think the only part you need to add is __get_kernel_nofault() > and __put_kernel_nofault(). You can see in mm/maccess.c > what the difference between the two versions in there is. > > Once you have those, you define HAVE_GET_KERNEL_NOFAULT > and then remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), > thread_info->addr_limit, KERNEL_DS, and USER_DS. Thanks for those hints! The attached initial patch below seems to work, it boots into systemd. It needs further cleanups though. I wonder if you should add a workaround for 32-bit kernels to not copy 64bit-wise, see my patch below in copy_from_kernel_nofault(): - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); Helge --- [PATCH] parisc: Implement __get/put_kernel_nofault() Add __get_kernel_nofault() and __put_kernel_nofault(), define HAVE_GET_KERNEL_NOFAULT and remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), thread_info->addr_limit, KERNEL_DS, and USER_DS. Signed-off-by: Helge Deller <deller@gmx.de> Suggested-by: Arnd Bergmann <arnd@kernel.org> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 3ae71994399c..b5bc346d464a 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -64,7 +64,6 @@ config PARISC select HAVE_KPROBES_ON_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS - select SET_FS help The PA-RISC microprocessor is designed by Hewlett-Packard and used diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h index b5fbcd2c1780..eeb7da064289 100644 --- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -101,10 +101,6 @@ DECLARE_PER_CPU(struct cpuinfo_parisc, cpu_data); #define CPU_HVERSION ((boot_cpu_data.hversion >> 4) & 0x0FFF) -typedef struct { - int seg; -} mm_segment_t; - #define ARCH_MIN_TASKALIGN 8 struct thread_struct { diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h index 0bd38a972cea..00ad50fef769 100644 --- a/arch/parisc/include/asm/thread_info.h +++ b/arch/parisc/include/asm/thread_info.h @@ -11,7 +11,6 @@ struct thread_info { struct task_struct *task; /* main task structure */ unsigned long flags; /* thread_info flags (see TIF_*) */ - mm_segment_t addr_limit; /* user-level address space limit */ __u32 cpu; /* current CPU */ int preempt_count; /* 0=premptable, <0=BUG; will also serve as bh-counter */ }; @@ -21,7 +20,6 @@ struct thread_info { .task = &tsk, \ .flags = 0, \ .cpu = 0, \ - .addr_limit = KERNEL_DS, \ .preempt_count = INIT_PREEMPT_COUNT, \ } diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index a4368731f2b4..6e0ca7756ceb 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -11,14 +11,6 @@ #include <linux/bug.h> #include <linux/string.h> -#define KERNEL_DS ((mm_segment_t){0}) -#define USER_DS ((mm_segment_t){1}) - -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -#define get_fs() (current_thread_info()->addr_limit) -#define set_fs(x) (current_thread_info()->addr_limit = (x)) - /* * Note that since kernel addresses are in a separate address space on * parisc, we don't need to do anything for access_ok(). @@ -33,11 +25,11 @@ #define get_user __get_user #if !defined(CONFIG_64BIT) -#define LDD_USER(val, ptr) __get_user_asm64(val, ptr) -#define STD_USER(x, ptr) __put_user_asm64(x, ptr) +#define LDD_USER(sr, val, ptr, err_label) __get_user_asm64(sr, val, ptr, err_label) +#define STD_USER(sr, x, ptr, err_label) __put_user_asm64(sr, x, ptr, err_label) #else -#define LDD_USER(val, ptr) __get_user_asm(val, "ldd", ptr) -#define STD_USER(x, ptr) __put_user_asm("std", x, ptr) +#define LDD_USER(sr, val, ptr, err_label) __get_user_asm(sr, val, "ldd", ptr, err_label) +#define STD_USER(sr, x, ptr, err_label) __put_user_asm(sr, "std", x, ptr, err_label) #endif /* @@ -67,28 +59,15 @@ struct exception_table_entry { #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\ ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1) -/* - * load_sr2() preloads the space register %%sr2 - based on the value of - * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which - * is 0), or with the current value of %%sr3 to access user space (USER_DS) - * memory. The following __get_user_asm() and __put_user_asm() functions have - * %%sr2 hard-coded to access the requested memory. - */ -#define load_sr2() \ - __asm__(" or,= %0,%%r0,%%r0\n\t" \ - " mfsp %%sr3,%0\n\t" \ - " mtsp %0,%%sr2\n\t" \ - : : "r"(get_fs()) : ) - -#define __get_user_internal(val, ptr) \ +#define __get_user_internal(sr, val, ptr, err_label) \ ({ \ register long __gu_err __asm__ ("r8") = 0; \ \ switch (sizeof(*(ptr))) { \ - case 1: __get_user_asm(val, "ldb", ptr); break; \ - case 2: __get_user_asm(val, "ldh", ptr); break; \ - case 4: __get_user_asm(val, "ldw", ptr); break; \ - case 8: LDD_USER(val, ptr); break; \ + case 1: __get_user_asm(sr, val, "ldb", ptr, err_label); break; \ + case 2: __get_user_asm(sr, val, "ldh", ptr, err_label); break; \ + case 4: __get_user_asm(sr, val, "ldw", ptr, err_label); break; \ + case 8: LDD_USER(sr, val, ptr, err_label); break; \ default: BUILD_BUG(); \ } \ \ @@ -97,26 +76,38 @@ struct exception_table_entry { #define __get_user(val, ptr) \ ({ \ - load_sr2(); \ - __get_user_internal(val, ptr); \ + __get_user_internal("%%sr3,", val, ptr, 9b); \ }) -#define __get_user_asm(val, ldx, ptr) \ +#define __get_user_asm(sr, val, ldx, ptr, err_label) \ { \ register long __gu_val; \ \ - __asm__("1: " ldx " 0(%%sr2,%2),%0\n" \ + __asm__("1: " ldx " 0(" sr "%2),%0\n" \ "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ : "=r"(__gu_val), "=r"(__gu_err) \ : "r"(ptr), "1"(__gu_err)); \ \ (val) = (__force __typeof__(*(ptr))) __gu_val; \ } +#define HAVE_GET_KERNEL_NOFAULT +#define __get_kernel_nofault(dst, src, type, err_label) \ +{ \ + type __z; \ + long __err; \ + __err = __get_user_internal("", __z, (type *)(src), 9b); \ + if (unlikely(__err)) \ + goto err_label; \ + else \ + *(type *)(dst) = __z; \ +} + + #if !defined(CONFIG_64BIT) -#define __get_user_asm64(val, ptr) \ +#define __get_user_asm64(sr, val, ptr, err_label) \ { \ union { \ unsigned long long l; \ @@ -124,11 +115,11 @@ struct exception_table_entry { } __gu_tmp; \ \ __asm__(" copy %%r0,%R0\n" \ - "1: ldw 0(%%sr2,%2),%0\n" \ - "2: ldw 4(%%sr2,%2),%R0\n" \ + "1: ldw 0(" sr "%2),%0\n" \ + "2: ldw 4(" sr "%2),%R0\n" \ "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, err_label) \ : "=&r"(__gu_tmp.l), "=r"(__gu_err) \ : "r"(ptr), "1"(__gu_err)); \ \ @@ -138,16 +129,16 @@ struct exception_table_entry { #endif /* !defined(CONFIG_64BIT) */ -#define __put_user_internal(x, ptr) \ +#define __put_user_internal(sr, x, ptr, err_label) \ ({ \ register long __pu_err __asm__ ("r8") = 0; \ __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x); \ \ switch (sizeof(*(ptr))) { \ - case 1: __put_user_asm("stb", __x, ptr); break; \ - case 2: __put_user_asm("sth", __x, ptr); break; \ - case 4: __put_user_asm("stw", __x, ptr); break; \ - case 8: STD_USER(__x, ptr); break; \ + case 1: __put_user_asm(sr, "stb", __x, ptr, err_label); break; \ + case 2: __put_user_asm(sr, "sth", __x, ptr, err_label); break; \ + case 4: __put_user_asm(sr, "stw", __x, ptr, err_label); break; \ + case 8: STD_USER(sr, __x, ptr, err_label); break; \ default: BUILD_BUG(); \ } \ \ @@ -156,10 +147,20 @@ struct exception_table_entry { #define __put_user(x, ptr) \ ({ \ - load_sr2(); \ - __put_user_internal(x, ptr); \ + __put_user_internal("%%sr3,", x, ptr, 9b); \ }) +#define __put_kernel_nofault(dst, src, type, err_label) \ +{ \ + type __z = *(type *)(src); \ + long __err; \ + __err = __put_user_internal("", __z, (type *)(dst), 9b);\ + if (unlikely(__err)) \ + goto err_label; \ +} + + + /* * The "__put_user/kernel_asm()" macros tell gcc they read from memory @@ -170,26 +171,26 @@ struct exception_table_entry { * r8 is already listed as err. */ -#define __put_user_asm(stx, x, ptr) \ - __asm__ __volatile__ ( \ - "1: " stx " %2,0(%%sr2,%1)\n" \ - "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ - : "=r"(__pu_err) \ +#define __put_user_asm(sr, stx, x, ptr, err_label) \ + __asm__ __volatile__ ( \ + "1: " stx " %2,0(" sr "%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + : "=r"(__pu_err) \ : "r"(ptr), "r"(x), "0"(__pu_err)) #if !defined(CONFIG_64BIT) -#define __put_user_asm64(__val, ptr) do { \ - __asm__ __volatile__ ( \ - "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)); \ +#define __put_user_asm64(sr, __val, ptr, err_label) do { \ + __asm__ __volatile__ ( \ + "1: stw %2,0(" sr "%1)\n" \ + "2: stw %R2,4(" sr "%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, err_label) \ + : "=r"(__pu_err) \ + : "r"(ptr), "r"(__val), "0"(__pu_err)); \ } while (0) #endif /* !defined(CONFIG_64BIT) */ @@ -205,7 +206,6 @@ extern __must_check long strnlen_user(const char __user *src, long n); /* * Complex access routines -- macros */ -#define user_addr_max() (~0UL) #define clear_user lclear_user #define __clear_user lclear_user diff --git a/arch/parisc/kernel/asm-offsets.c b/arch/parisc/kernel/asm-offsets.c index 33113ba24054..7c83915e4aed 100644 --- a/arch/parisc/kernel/asm-offsets.c +++ b/arch/parisc/kernel/asm-offsets.c @@ -230,7 +230,7 @@ int main(void) DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); - DEFINE(TI_SEGMENT, offsetof(struct thread_info, addr_limit)); +// DEFINE(TI_SEGMENT, offsetof(struct thread_info, addr_limit)); DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count)); DEFINE(THREAD_SZ, sizeof(struct thread_info)); /* THREAD_SZ_ALGN includes space for a stack frame. */ diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S index 0aad5ce89f4d..29eafd963ac0 100644 --- a/arch/parisc/lib/lusercopy.S +++ b/arch/parisc/lib/lusercopy.S @@ -34,11 +34,11 @@ */ .macro get_sr - mfctl %cr30,%r1 - ldw TI_SEGMENT(%r1),%r22 +// mfctl %cr30,%r1 +// ldw TI_SEGMENT(%r1),%r22 mfsp %sr3,%r1 - or,<> %r22,%r0,%r0 - copy %r0,%r1 +// or,<> %r22,%r0,%r0 +// copy %r0,%r1 mtsp %r1,%sr1 .endm diff --git a/mm/maccess.c b/mm/maccess.c index 3bd70405f2d8..85eb86d6cab4 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -28,7 +28,9 @@ long copy_from_kernel_nofault(void *dst, const void *src, size_t size) return -ERANGE; pagefault_disable(); - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); copy_from_kernel_nofault_loop(dst, src, size, u32, Efault); copy_from_kernel_nofault_loop(dst, src, size, u16, Efault); copy_from_kernel_nofault_loop(dst, src, size, u8, Efault); @@ -51,7 +53,9 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); long copy_to_kernel_nofault(void *dst, const void *src, size_t size) { pagefault_disable(); - copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); copy_to_kernel_nofault_loop(dst, src, size, u32, Efault); copy_to_kernel_nofault_loop(dst, src, size, u16, Efault); copy_to_kernel_nofault_loop(dst, src, size, u8, Efault);
On Thu, Sep 9, 2021 at 4:03 AM Helge Deller <deller@gmx.de> wrote: > * Arnd Bergmann <arnd@kernel.org>: > > > > I think the only part you need to add is __get_kernel_nofault() > > and __put_kernel_nofault(). You can see in mm/maccess.c > > what the difference between the two versions in there is. > > > > Once you have those, you define HAVE_GET_KERNEL_NOFAULT > > and then remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), > > thread_info->addr_limit, KERNEL_DS, and USER_DS. > > Thanks for those hints! > The attached initial patch below seems to work, it boots into systemd. > It needs further cleanups though. > > I wonder if you should add a workaround for 32-bit kernels > to not copy 64bit-wise, see my patch below in > copy_from_kernel_nofault(): > > - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); > + /* avoid 64-bit accesses on 32-bit platforms */ > + if (sizeof(unsigned long) > 4) > + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); I would assume that the 8-byte copy would just turn into two 4-byte accesses here, with exactly the same behavior. Note that this function changed in 5.15 when I added support for architectures without unaligned access. You need to include 132b548af559 ("mm/maccess: fix unaligned copy_{from,to}_kernel_nofault") here for parsic as well, I assume. If you prefer to avoid the 8-byte access, this could be done in the 'align = (unsigned long)dst | (unsigned long)src;' statement by masking out that bit. > [PATCH] parisc: Implement __get/put_kernel_nofault() > > Add __get_kernel_nofault() and __put_kernel_nofault(), define > HAVE_GET_KERNEL_NOFAULT and remove CONFIG_SET_FS, set_fs(), get_fs(), > load_sr2(), thread_info->addr_limit, KERNEL_DS, and USER_DS. > > Signed-off-by: Helge Deller <deller@gmx.de> > Suggested-by: Arnd Bergmann <arnd@kernel.org> Looks good to me overall, with the missing cleanups added. You should probably include a TASK_SIZE_MAX definition that matches the old user_addr_max() to avoid looking up the per-task value every time. Arnd
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 95d4bbf4e455..3ae71994399c 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -10,7 +10,6 @@ config PARISC select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_UBSAN_SANITIZE_ALL - select ARCH_HAS_STRNLEN_USER select ARCH_NO_SG_CHAIN select ARCH_SUPPORTS_HUGETLBFS if PA20 select ARCH_SUPPORTS_MEMORY_FAILURE diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index ed2cd4fb479b..2442ed2929ae 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -201,13 +201,12 @@ struct exception_table_entry { extern long strncpy_from_user(char *, const char __user *, long); extern unsigned lclear_user(void __user *, unsigned long); -extern long lstrnlen_user(const char __user *, long); +extern __must_check long strnlen_user(const char __user *src, long n); /* * Complex access routines -- macros */ -#define user_addr_max() (~0UL) +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) -#define strnlen_user lstrnlen_user #define clear_user lclear_user #define __clear_user lclear_user diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c index e8a6a751dfd8..00297e8e1c88 100644 --- a/arch/parisc/kernel/parisc_ksyms.c +++ b/arch/parisc/kernel/parisc_ksyms.c @@ -32,7 +32,6 @@ EXPORT_SYMBOL(__xchg64); #include <linux/uaccess.h> EXPORT_SYMBOL(lclear_user); -EXPORT_SYMBOL(lstrnlen_user); #ifndef CONFIG_64BIT /* Needed so insmod can set dp value */ diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S index 36d6a8638ead..0aad5ce89f4d 100644 --- a/arch/parisc/lib/lusercopy.S +++ b/arch/parisc/lib/lusercopy.S @@ -67,40 +67,6 @@ $lclu_done: ENDPROC_CFI(lclear_user) - /* - * long lstrnlen_user(char *s, long n) - * - * Returns 0 if exception before zero byte or reaching N, - * N+1 if N would be exceeded, - * else strlen + 1 (i.e. includes zero byte). - */ - -ENTRY_CFI(lstrnlen_user) - comib,= 0,%r25,$lslen_nzero - copy %r26,%r24 - get_sr -1: ldbs,ma 1(%sr1,%r26),%r1 -$lslen_loop: - comib,=,n 0,%r1,$lslen_done - addib,<> -1,%r25,$lslen_loop -2: ldbs,ma 1(%sr1,%r26),%r1 -$lslen_done: - bv %r0(%r2) - sub %r26,%r24,%r28 - -$lslen_nzero: - b $lslen_done - ldo 1(%r26),%r26 /* special case for N == 0 */ - -3: b $lslen_done - copy %r24,%r26 /* reset r26 so 0 is returned on fault */ - - ASM_EXCEPTIONTABLE_ENTRY(1b,3b) - ASM_EXCEPTIONTABLE_ENTRY(2b,3b) - -ENDPROC_CFI(lstrnlen_user) - - /* * unsigned long pa_memcpy(void *dstp, const void *srcp, unsigned long len) *
As suggested by Arnd Bergmann, drop the parisc version of strnlen_user() and switch to the generic version. user_addr_max() was wrong too, fix it by using TASK_SIZE. Suggested-by: Arnd Bergmann <arnd@kernel.org> Signed-off-by: Helge Deller <deller@gmx.de> --- arch/parisc/Kconfig | 1 - arch/parisc/include/asm/uaccess.h | 5 ++--- arch/parisc/kernel/parisc_ksyms.c | 1 - arch/parisc/lib/lusercopy.S | 34 ------------------------------- 4 files changed, 2 insertions(+), 39 deletions(-) -- 2.31.1