[PATCH 1/4] parisc: Drop strnlen_user() in favour of generic version

From: Helge Deller <deller@gmx.de>
To: linux-parisc@vger.kernel.org
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
	John David Anglin <dave.anglin@bell.net>,
	Arnd Bergmann <arnd@kernel.org>
Subject: [PATCH 1/4] parisc: Drop strnlen_user() in favour of generic version
Date: Wed,  8 Sep 2021 22:44:02 +0200	[thread overview]
Message-ID: <20210908204405.127665-1-deller@gmx.de> (raw)

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(-)

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)
  *
--
2.31.1

