Message-Id: <2153a67890e24751c94029ef42e3a17c09249c8a.1297842537.git.gxt@mprc.pku.edu.cn>
In-Reply-To: <[email protected]>
References: <[email protected]>
From: GuanXuetao <[email protected]>
Date: Sat, 15 Jan 2011 18:22:46 +0800
This patch implements low-level uaccess libraries.
Signed-off-by: Guan Xuetao <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
---
arch/unicore32/include/asm/uaccess.h | 47 +++++++
arch/unicore32/lib/clear_user.S | 57 +++++++++
arch/unicore32/lib/copy_from_user.S | 108 ++++++++++++++++
arch/unicore32/lib/copy_page.S | 39 ++++++
arch/unicore32/lib/copy_template.S | 214 ++++++++++++++++++++++++++++++++
arch/unicore32/lib/copy_to_user.S | 96 ++++++++++++++
arch/unicore32/lib/strncpy_from_user.S | 45 +++++++
arch/unicore32/lib/strnlen_user.S | 42 ++++++
8 files changed, 648 insertions(+), 0 deletions(-)
create mode 100644 arch/unicore32/include/asm/uaccess.h
create mode 100644 arch/unicore32/lib/clear_user.S
create mode 100644 arch/unicore32/lib/copy_from_user.S
create mode 100644 arch/unicore32/lib/copy_page.S
create mode 100644 arch/unicore32/lib/copy_template.S
create mode 100644 arch/unicore32/lib/copy_to_user.S
create mode 100644 arch/unicore32/lib/strncpy_from_user.S
create mode 100644 arch/unicore32/lib/strnlen_user.S
diff --git a/arch/unicore32/include/asm/uaccess.h b/arch/unicore32/include/asm/uaccess.h
new file mode 100644
index 0000000..5ff23bc
--- /dev/null
+++ b/arch/unicore32/include/asm/uaccess.h
@@ -0,0 +1,47 @@
+/*
+ * linux/arch/unicore32/include/asm/uaccess.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __UNICORE_UACCESS_H__
+#define __UNICORE_UACCESS_H__
+
+#include <linux/thread_info.h>
+#include <linux/errno.h>
+
+#include <asm/memory.h>
+#include <asm/system.h>
+
+#define __copy_from_user __copy_from_user
+#define __copy_to_user __copy_to_user
+#define __strncpy_from_user __strncpy_from_user
+#define strnlen_user strnlen_user
+#define __clear_user __clear_user
+
+#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
+#define __user_ok(addr, size) (((size) <= TASK_SIZE) \
+ && ((addr) <= TASK_SIZE - (size)))
+#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
+
+extern unsigned long __must_check
+__copy_from_user(void *to, const void __user *from, unsigned long n);
+extern unsigned long __must_check
+__copy_to_user(void __user *to, const void *from, unsigned long n);
+extern unsigned long __must_check
+__clear_user(void __user *addr, unsigned long n);
+extern unsigned long __must_check
+__strncpy_from_user(char *to, const char __user *from, unsigned long count);
+extern unsigned long
+__strnlen_user(const char __user *s, long n);
+
+#include <asm-generic/uaccess.h>
+
+extern int fixup_exception(struct pt_regs *regs);
+
+#endif /* __UNICORE_UACCESS_H__ */
diff --git a/arch/unicore32/lib/clear_user.S b/arch/unicore32/lib/clear_user.S
new file mode 100644
index 0000000..20047f7
--- /dev/null
+++ b/arch/unicore32/lib/clear_user.S
@@ -0,0 +1,57 @@
+/*
+ * linux/arch/unicore32/lib/clear_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+ .text
+
+/* Prototype: int __clear_user(void *addr, size_t sz)
+ * Purpose : clear some user memory
+ * Params : addr - user memory address to clear
+ * : sz - number of bytes to clear
+ * Returns : number of bytes NOT cleared
+ */
+WEAK(__clear_user)
+ stm.w (lr), [sp-]
+ stm.w (r1), [sp-]
+ mov r2, #0
+ csub.a r1, #4
+ bsl 2f
+ and.a ip, r0, #3
+ beq 1f
+ csub.a ip, #2
+ strusr r2, r0, 1
+ strusr r2, r0, 1, el
+ strusr r2, r0, 1, sl
+ rsub ip, ip, #4
+ sub r1, r1, ip @ 7 6 5 4 3 2 1
+1: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
+ strusr r2, r0, 4, ns, rept=2
+ bns 1b
+ add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3
+ strusr r2, r0, 4, ns
+2: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
+ strusr r2, r0, 1, ne, rept=2
+ cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1
+ beq 3f
+USER( stb.u r2, [r0])
+3: mov r0, #0
+ ldm.w (r1), [sp]+
+ ldm.w (pc), [sp]+
+ENDPROC(__clear_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+9001: ldm.w (r0), [sp]+
+ ldm.w (pc), [sp]+
+ .popsection
+
diff --git a/arch/unicore32/lib/copy_from_user.S b/arch/unicore32/lib/copy_from_user.S
new file mode 100644
index 0000000..ab0767e
--- /dev/null
+++ b/arch/unicore32/lib/copy_from_user.S
@@ -0,0 +1,108 @@
+/*
+ * linux/arch/unicore32/lib/copy_from_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Prototype:
+ *
+ * size_t __copy_from_user(void *to, const void *from, size_t n)
+ *
+ * Purpose:
+ *
+ * copy a block to kernel memory from user memory
+ *
+ * Params:
+ *
+ * to = kernel memory
+ * from = user memory
+ * n = number of bytes to copy
+ *
+ * Return value:
+ *
+ * Number of bytes NOT copied.
+ */
+
+ .macro ldr1w ptr reg abort
+ ldrusr \reg, \ptr, 4, abort=\abort
+ .endm
+
+ .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
+100: ldm.w (\reg1, \reg2, \reg3, \reg4), [\ptr]+
+ .pushsection __ex_table, "a"
+ .align 3
+ .long 100b, \abort
+ .popsection
+ .endm
+
+ .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+100: ldm.w (\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8), [\ptr]+
+ .pushsection __ex_table, "a"
+ .align 3
+ .long 100b, \abort
+ .popsection
+ .endm
+
+ .macro ldr1b ptr reg cond=al abort
+ ldrusr \reg, \ptr, 1, \cond, abort=\abort
+ .endm
+
+ .macro str1w ptr reg abort
+ stw.w \reg, [\ptr]+, #4
+ .endm
+
+ .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ stm.w (\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8), [\ptr]+
+ .endm
+
+ .macro str1b ptr reg cond=al abort
+ .ifnc \cond, al
+ b\cond 201f
+ b 202f
+ .endif
+201: stb.w \reg, [\ptr]+, #1
+202:
+ .endm
+
+ .macro enter
+ mov r3, #0
+ stm.w (r0, r2, r3), [sp-]
+ .endm
+
+ .macro exit
+ add sp, sp, #8
+ ldm.w (r0), [sp]+
+ mov pc, lr
+ .endm
+
+ .text
+
+ENTRY(__copy_from_user)
+
+#include "copy_template.S"
+
+ENDPROC(__copy_from_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+ copy_abort_preamble
+ ldm.w (r1, r2), [sp]+
+ sub r3, r0, r1
+ rsub r2, r3, r2
+ stw r2, [sp]
+ mov r1, #0
+ b.l memset
+ ldw.w r0, [sp]+, #4
+ copy_abort_end
+ .popsection
+
diff --git a/arch/unicore32/lib/copy_page.S b/arch/unicore32/lib/copy_page.S
new file mode 100644
index 0000000..3a448d7
--- /dev/null
+++ b/arch/unicore32/lib/copy_page.S
@@ -0,0 +1,39 @@
+/*
+ * linux/arch/unicore32/lib/copy_page.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * ASM optimised string functions
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <generated/asm-offsets.h>
+#include <asm/cache.h>
+
+#define COPY_COUNT (PAGE_SZ/256)
+
+ .text
+ .align 5
+/*
+ * UniCore optimised copy_page routine
+ */
+ENTRY(copy_page)
+ stm.w (r17 - r19, lr), [sp-]
+ mov r17, r0
+ mov r18, r1
+ mov r19, #COPY_COUNT
+1:
+ .rept 4
+ ldm.w (r0 - r15), [r18]+
+ stm.w (r0 - r15), [r17]+
+ .endr
+ sub.a r19, r19, #1
+ bne 1b
+ ldm.w (r17 - r19, pc), [sp]+
+ENDPROC(copy_page)
diff --git a/arch/unicore32/lib/copy_template.S b/arch/unicore32/lib/copy_template.S
new file mode 100644
index 0000000..524287f
--- /dev/null
+++ b/arch/unicore32/lib/copy_template.S
@@ -0,0 +1,214 @@
+/*
+ * linux/arch/unicore32/lib/copy_template.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * Theory of operation
+ * -------------------
+ *
+ * This file provides the core code for a forward memory copy used in
+ * the implementation of memcopy(), copy_to_user() and copy_from_user().
+ *
+ * The including file must define the following accessor macros
+ * according to the need of the given function:
+ *
+ * ldr1w ptr reg abort
+ *
+ * This loads one word from 'ptr', stores it in 'reg' and increments
+ * 'ptr' to the next word. The 'abort' argument is used for fixup tables.
+ *
+ * ldr4w ptr reg1 reg2 reg3 reg4 abort
+ * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ *
+ * This loads four or eight words starting from 'ptr', stores them
+ * in provided registers and increments 'ptr' past those words.
+ * The'abort' argument is used for fixup tables.
+ *
+ * ldr1b ptr reg cond abort
+ *
+ * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte.
+ * It also must apply the condition code if provided, otherwise the
+ * "al" condition is assumed by default.
+ *
+ * str1w ptr reg abort
+ * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ * str1b ptr reg cond abort
+ *
+ * Same as their ldr* counterparts, but data is stored to 'ptr' location
+ * rather than being loaded.
+ *
+ * enter
+ *
+ * Preserve the provided registers on the stack plus any additional
+ * data as needed by the implementation including this code. Called
+ * upon code entry.
+ *
+ * exit
+ *
+ * Restore registers with the values previously saved with the
+ * 'preserv' macro. Called upon code termination.
+ */
+
+
+ enter
+
+ sub.a r2, r2, #4
+ bsl 8f
+ and.a ip, r0, #3
+ bne 9f
+ and.a ip, r1, #3
+ bne 10f
+
+1: sub.a r2, r2, #(28)
+ stm.w (r5 - r8), [sp-]
+ bsl 5f
+
+3:
+4: ldr8w r1, r3, r4, r5, r6, r7, r8, r10, r11, abort=20f
+ sub.a r2, r2, #32
+ str8w r0, r3, r4, r5, r6, r7, r8, r10, r11, abort=20f
+ beg 3b
+
+5: and.a ip, r2, #28
+ rsub ip, ip, #32
+ beq 7f
+ add pc, pc, ip @ C is always clear here
+ nop
+
+ ldr1w r1, r3, abort=20f
+ ldr1w r1, r4, abort=20f
+ ldr1w r1, r5, abort=20f
+ ldr1w r1, r6, abort=20f
+ ldr1w r1, r7, abort=20f
+ ldr1w r1, r8, abort=20f
+ ldr1w r1, r11, abort=20f
+
+ add pc, pc, ip
+ nop
+
+ str1w r0, r3, abort=20f
+ str1w r0, r4, abort=20f
+ str1w r0, r5, abort=20f
+ str1w r0, r6, abort=20f
+ str1w r0, r7, abort=20f
+ str1w r0, r8, abort=20f
+ str1w r0, r11, abort=20f
+
+7: ldm.w (r5 - r8), [sp]+
+
+8: mov.a r2, r2 << #31
+ ldr1b r1, r3, ne, abort=21f
+ ldr1b r1, r4, ea, abort=21f
+ ldr1b r1, r10, ea, abort=21f
+ str1b r0, r3, ne, abort=21f
+ str1b r0, r4, ea, abort=21f
+ str1b r0, r10, ea, abort=21f
+
+ exit
+
+9: rsub ip, ip, #4
+ csub.a ip, #2
+ ldr1b r1, r3, sg, abort=21f
+ ldr1b r1, r4, eg, abort=21f
+ ldr1b r1, r11, abort=21f
+ str1b r0, r3, sg, abort=21f
+ str1b r0, r4, eg, abort=21f
+ sub.a r2, r2, ip
+ str1b r0, r11, abort=21f
+ bsl 8b
+ and.a ip, r1, #3
+ beq 1b
+
+10: andn r1, r1, #3
+ csub.a ip, #2
+ ldr1w r1, r11, abort=21f
+ beq 17f
+ bsg 18f
+
+
+ .macro forward_copy_shift a b
+
+ sub.a r2, r2, #28
+ bsl 14f
+
+11: stm.w (r5 - r9), [sp-]
+
+12:
+ ldr4w r1, r4, r5, r6, r7, abort=19f
+ mov r3, r11 pull #\a
+ sub.a r2, r2, #32
+ ldr4w r1, r8, r9, r10, r11, abort=19f
+ or r3, r3, r4 push #\b
+ mov r4, r4 pull #\a
+ or r4, r4, r5 push #\b
+ mov r5, r5 pull #\a
+ or r5, r5, r6 push #\b
+ mov r6, r6 pull #\a
+ or r6, r6, r7 push #\b
+ mov r7, r7 pull #\a
+ or r7, r7, r8 push #\b
+ mov r8, r8 pull #\a
+ or r8, r8, r9 push #\b
+ mov r9, r9 pull #\a
+ or r9, r9, r10 push #\b
+ mov r10, r10 pull #\a
+ or r10, r10, r11 push #\b
+ str8w r0, r3, r4, r5, r6, r7, r8, r9, r10, , abort=19f
+ beg 12b
+
+ ldm.w (r5 - r9), [sp]+
+
+14: and.a ip, r2, #28
+ beq 16f
+
+15: mov r3, r11 pull #\a
+ ldr1w r1, r11, abort=21f
+ sub.a ip, ip, #4
+ or r3, r3, r11 push #\b
+ str1w r0, r3, abort=21f
+ bsg 15b
+
+16: sub r1, r1, #(\b / 8)
+ b 8b
+
+ .endm
+
+
+ forward_copy_shift a=8 b=24
+
+17: forward_copy_shift a=16 b=16
+
+18: forward_copy_shift a=24 b=8
+
+
+/*
+ * Abort preamble and completion macros.
+ * If a fixup handler is required then those macros must surround it.
+ * It is assumed that the fixup code will handle the private part of
+ * the exit macro.
+ */
+
+ .macro copy_abort_preamble
+19: ldm.w (r5 - r9), [sp]+
+ b 21f
+299: .word 0 @ store lr
+ @ to avoid function call in fixup
+20: ldm.w (r5 - r8), [sp]+
+21:
+ adr r1, 299b
+ stw lr, [r1]
+ .endm
+
+ .macro copy_abort_end
+ adr lr, 299b
+ ldw pc, [lr]
+ .endm
+
diff --git a/arch/unicore32/lib/copy_to_user.S b/arch/unicore32/lib/copy_to_user.S
new file mode 100644
index 0000000..6e22151
--- /dev/null
+++ b/arch/unicore32/lib/copy_to_user.S
@@ -0,0 +1,96 @@
+/*
+ * linux/arch/unicore32/lib/copy_to_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Prototype:
+ *
+ * size_t __copy_to_user(void *to, const void *from, size_t n)
+ *
+ * Purpose:
+ *
+ * copy a block to user memory from kernel memory
+ *
+ * Params:
+ *
+ * to = user memory
+ * from = kernel memory
+ * n = number of bytes to copy
+ *
+ * Return value:
+ *
+ * Number of bytes NOT copied.
+ */
+
+ .macro ldr1w ptr reg abort
+ ldw.w \reg, [\ptr]+, #4
+ .endm
+
+ .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
+ ldm.w (\reg1, \reg2, \reg3, \reg4), [\ptr]+
+ .endm
+
+ .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ ldm.w (\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8), [\ptr]+
+ .endm
+
+ .macro ldr1b ptr reg cond=al abort
+ notcond \cond, .+8
+ ldb.w \reg, [\ptr]+, #1
+ .endm
+
+ .macro str1w ptr reg abort
+ strusr \reg, \ptr, 4, abort=\abort
+ .endm
+
+ .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+100: stm.w (\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8), [\ptr]+
+
+ .pushsection __ex_table, "a"
+ .long 100b, \abort
+ .popsection
+ .endm
+
+ .macro str1b ptr reg cond=al abort
+ strusr \reg, \ptr, 1, \cond, abort=\abort
+ .endm
+
+ .macro enter
+ mov r3, #0
+ stm.w (r0, r2, r3), [sp-]
+ .endm
+
+ .macro exit
+ add sp, sp, #8
+ ldm.w (r0), [sp]+
+ mov pc, lr
+ .endm
+
+ .text
+
+WEAK(__copy_to_user)
+
+#include "copy_template.S"
+
+ENDPROC(__copy_to_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+ copy_abort_preamble
+ ldm.w (r1, r2, r3), [sp]+
+ sub r0, r0, r1
+ rsub r0, r0, r2
+ copy_abort_end
+ .popsection
+
diff --git a/arch/unicore32/lib/strncpy_from_user.S b/arch/unicore32/lib/strncpy_from_user.S
new file mode 100644
index 0000000..ff6c304
--- /dev/null
+++ b/arch/unicore32/lib/strncpy_from_user.S
@@ -0,0 +1,45 @@
+/*
+ * linux/arch/unicore32/lib/strncpy_from_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/errno.h>
+
+ .text
+ .align 5
+
+/*
+ * Copy a string from user space to kernel space.
+ * r0 = dst, r1 = src, r2 = byte length
+ * returns the number of characters copied (strlen of copied string),
+ * -EFAULT on exception, or "len" if we fill the whole buffer
+ */
+ENTRY(__strncpy_from_user)
+ mov ip, r1
+1: sub.a r2, r2, #1
+ ldrusr r3, r1, 1, ns
+ bfs 2f
+ stb.w r3, [r0]+, #1
+ cxor.a r3, #0
+ bne 1b
+ sub r1, r1, #1 @ take NUL character out of count
+2: sub r0, r1, ip
+ mov pc, lr
+ENDPROC(__strncpy_from_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+9001: mov r3, #0
+ stb r3, [r0+], #0 @ null terminate
+ mov r0, #-EFAULT
+ mov pc, lr
+ .popsection
+
diff --git a/arch/unicore32/lib/strnlen_user.S b/arch/unicore32/lib/strnlen_user.S
new file mode 100644
index 0000000..7586303
--- /dev/null
+++ b/arch/unicore32/lib/strnlen_user.S
@@ -0,0 +1,42 @@
+/*
+ * linux/arch/unicore32/lib/strnlen_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/errno.h>
+
+ .text
+ .align 5
+
+/* Prototype: unsigned long __strnlen_user(const char *str, long n)
+ * Purpose : get length of a string in user memory
+ * Params : str - address of string in user memory
+ * Returns : length of string *including terminator*
+ * or zero on exception, or n + 1 if too long
+ */
+ENTRY(__strnlen_user)
+ mov r2, r0
+1:
+ ldrusr r3, r0, 1
+ cxor.a r3, #0
+ beq 2f
+ sub.a r1, r1, #1
+ bne 1b
+ add r0, r0, #1
+2: sub r0, r0, r2
+ mov pc, lr
+ENDPROC(__strnlen_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+9001: mov r0, #0
+ mov pc, lr
+ .popsection
--
1.6.2.2
On Wednesday 16 February 2011, Guan Xuetao wrote:
> +
> +#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
> +#define __user_ok(addr, size) (((size) <= TASK_SIZE) \
> + && ((addr) <= TASK_SIZE - (size)))
> +#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
A nice trick to simplify this is to introduce a per-process variable for comparing
the pointer, set_fs() then sets this variable to either TASK_SIZE or
UINT_MAX.
This saves one conditional branch for each call to __access_ok.
Arnd
> -----Original Message-----
> From: Arnd Bergmann [mailto:[email protected]]
> Sent: Friday, February 18, 2011 1:45 AM
> To: Guan Xuetao
> Cc: [email protected]; [email protected]; 'Greg KH'
> Subject: Re: [PATCH 05/12] unicore32 additional architecture files: low-level lib: uaccess
>
> On Wednesday 16 February 2011, Guan Xuetao wrote:
> > +
> > +#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
> > +#define __user_ok(addr, size) (((size) <= TASK_SIZE) \
> > + && ((addr) <= TASK_SIZE - (size)))
> > +#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
>
> A nice trick to simplify this is to introduce a per-process variable for comparing
> the pointer, set_fs() then sets this variable to either TASK_SIZE or
> UINT_MAX.
Perhaps like this:
1. add a member named kaddr in thread_info
2. add following assignment codes in set_fs:
current_thread_info()->kaddr = segment_eq(fs, KERNEL_DS) ? UINT_MAX : TASK_SIZE;
3. then __access_ok will be:
#define addr
#define __access_ok(addr, size) (((size) <= TASK_SIZE) \
&& ((addr) <= current_thread_info()->kaddr) - (size)))
>
> This saves one conditional branch for each call to __access_ok.
>
> Arnd
On Sunday 27 February 2011, Guan Xuetao wrote:
> > -----Original Message-----
> > From: Arnd Bergmann [mailto:[email protected]]
> > Sent: Friday, February 18, 2011 1:45 AM
> > To: Guan Xuetao
> > Cc: [email protected]; [email protected]; 'Greg KH'
> > Subject: Re: [PATCH 05/12] unicore32 additional architecture files: low-level lib: uaccess
> >
> > On Wednesday 16 February 2011, Guan Xuetao wrote:
> > > +
> > > +#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
> > > +#define __user_ok(addr, size) (((size) <= TASK_SIZE) \
> > > + && ((addr) <= TASK_SIZE - (size)))
> > > +#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
> >
> > A nice trick to simplify this is to introduce a per-process variable for comparing
> > the pointer, set_fs() then sets this variable to either TASK_SIZE or
> > UINT_MAX.
>
> Perhaps like this:
> 1. add a member named kaddr in thread_info
> 2. add following assignment codes in set_fs:
> current_thread_info()->kaddr = segment_eq(fs, KERNEL_DS) ? UINT_MAX : TASK_SIZE;
> 3. then __access_ok will be:
> #define addr
> #define __access_ok(addr, size) (((size) <= TASK_SIZE) \
> && ((addr) <= current_thread_info()->kaddr) - (size)))
That would also work. What I meant was to have
#define set_fs(fs) \
do { current_thread_info()->kaddr = (fs); } while (0)
#define KERNEL_DS UINT_MAX
#define USER_DS TASK_SIZE
Either way is fine with me, just choose whichever works best for you in terms of code size.
Arnd
> -----Original Message-----
> From: Arnd Bergmann [mailto:[email protected]]
> Sent: Monday, February 28, 2011 1:22 AM
> To: Guan Xuetao
> Cc: [email protected]; [email protected]; 'Greg KH'
> Subject: Re: [PATCH 05/12] unicore32 additional architecture files: low-level lib: uaccess
>
> On Sunday 27 February 2011, Guan Xuetao wrote:
> > > -----Original Message-----
> > > From: Arnd Bergmann [mailto:[email protected]]
> > > Sent: Friday, February 18, 2011 1:45 AM
> > > To: Guan Xuetao
> > > Cc: [email protected]; [email protected]; 'Greg KH'
> > > Subject: Re: [PATCH 05/12] unicore32 additional architecture files: low-level lib: uaccess
> > >
> > > On Wednesday 16 February 2011, Guan Xuetao wrote:
> > > > +
> > > > +#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
> > > > +#define __user_ok(addr, size) (((size) <= TASK_SIZE) \
> > > > + && ((addr) <= TASK_SIZE - (size)))
> > > > +#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
> > >
> > > A nice trick to simplify this is to introduce a per-process variable for comparing
> > > the pointer, set_fs() then sets this variable to either TASK_SIZE or
> > > UINT_MAX.
> >
> > Perhaps like this:
> > 1. add a member named kaddr in thread_info
> > 2. add following assignment codes in set_fs:
> > current_thread_info()->kaddr = segment_eq(fs, KERNEL_DS) ? UINT_MAX : TASK_SIZE;
> > 3. then __access_ok will be:
> > #define addr
> > #define __access_ok(addr, size) (((size) <= TASK_SIZE) \
> > && ((addr) <= current_thread_info()->kaddr) - (size)))
>
> That would also work. What I meant was to have
>
> #define set_fs(fs) \
> do { current_thread_info()->kaddr = (fs); } while (0)
>
> #define KERNEL_DS UINT_MAX
> #define USER_DS TASK_SIZE
>
> Either way is fine with me, just choose whichever works best for you in terms of code size.
I can't find the difference between this way and the way in asm-generic/uaccess.h.
Perhaps, under this idea, __kernel_ok could be ignored.
>
> Arnd
Thanks & Regards.
Guan Xuetao