4b9d2a731c
Use register r29 instead of register r8 to signal faults when accessing user memory. In case of faults, the fixup routine will store -EFAULT in this register. This change saves up to 752 bytes on a 32bit kernel, partly because the compiler doesn't need to save and restore the old r8 value on the stack. bloat-o-meter results for usage with r29 register: add/remove: 0/0 grow/shrink: 23/86 up/down: 228/-980 (-752) bloat-o-meter results for usage with r28 register: add/remove: 0/0 grow/shrink: 28/83 up/down: 296/-956 (-660) Signed-off-by: Helge Deller <deller@gmx.de>
227 lines
6.3 KiB
C
227 lines
6.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PARISC_UACCESS_H
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#define __PARISC_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <asm/page.h>
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#include <asm/cache.h>
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#include <linux/bug.h>
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#include <linux/string.h>
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/*
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* Note that since kernel addresses are in a separate address space on
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* parisc, we don't need to do anything for access_ok().
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* We just let the page fault handler do the right thing. This also means
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* that put_user is the same as __put_user, etc.
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*/
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#define access_ok(uaddr, size) \
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( (uaddr) == (uaddr) )
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#define put_user __put_user
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#define get_user __get_user
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#if !defined(CONFIG_64BIT)
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#define LDD_USER(sr, val, ptr) __get_user_asm64(sr, val, ptr)
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#define STD_USER(sr, x, ptr) __put_user_asm64(sr, x, ptr)
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#else
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#define LDD_USER(sr, val, ptr) __get_user_asm(sr, val, "ldd", ptr)
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#define STD_USER(sr, x, ptr) __put_user_asm(sr, "std", x, ptr)
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#endif
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/*
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* The exception table contains two values: the first is the relative offset to
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* the address of the instruction that is allowed to fault, and the second is
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* the relative offset to the address of the fixup routine. Since relative
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* addresses are used, 32bit values are sufficient even on 64bit kernel.
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*/
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#define ARCH_HAS_RELATIVE_EXTABLE
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struct exception_table_entry {
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int insn; /* relative address of insn that is allowed to fault. */
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int fixup; /* relative address of fixup routine */
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};
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#define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
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".section __ex_table,\"aw\"\n" \
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".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
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".previous\n"
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/*
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* ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
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* (with lowest bit set) for which the fault handler in fixup_exception() will
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* load -EFAULT into %r29 for a read or write fault, and zeroes the target
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* register in case of a read fault in get_user().
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*/
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#define ASM_EXCEPTIONTABLE_REG 29
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#define ASM_EXCEPTIONTABLE_VAR(__variable) \
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register long __variable __asm__ ("r29") = 0
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#define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\
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ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1)
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#define __get_user_internal(sr, val, ptr) \
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({ \
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ASM_EXCEPTIONTABLE_VAR(__gu_err); \
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\
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switch (sizeof(*(ptr))) { \
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case 1: __get_user_asm(sr, val, "ldb", ptr); break; \
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case 2: __get_user_asm(sr, val, "ldh", ptr); break; \
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case 4: __get_user_asm(sr, val, "ldw", ptr); break; \
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case 8: LDD_USER(sr, val, ptr); break; \
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default: BUILD_BUG(); \
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} \
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\
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__gu_err; \
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})
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#define __get_user(val, ptr) \
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({ \
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__get_user_internal("%%sr3,", val, ptr); \
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})
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#define __get_user_asm(sr, val, ldx, ptr) \
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{ \
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register long __gu_val; \
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\
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__asm__("1: " ldx " 0(" sr "%2),%0\n" \
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"9:\n" \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
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: "=r"(__gu_val), "=r"(__gu_err) \
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: "r"(ptr), "1"(__gu_err)); \
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\
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(val) = (__force __typeof__(*(ptr))) __gu_val; \
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}
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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{ \
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type __z; \
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long __err; \
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__err = __get_user_internal("%%sr0,", __z, (type *)(src)); \
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if (unlikely(__err)) \
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goto err_label; \
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else \
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*(type *)(dst) = __z; \
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}
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#if !defined(CONFIG_64BIT)
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#define __get_user_asm64(sr, val, ptr) \
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{ \
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union { \
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unsigned long long l; \
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__typeof__(*(ptr)) t; \
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} __gu_tmp; \
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\
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__asm__(" copy %%r0,%R0\n" \
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"1: ldw 0(" sr "%2),%0\n" \
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"2: ldw 4(" sr "%2),%R0\n" \
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"9:\n" \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
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: "=&r"(__gu_tmp.l), "=r"(__gu_err) \
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: "r"(ptr), "1"(__gu_err)); \
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\
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(val) = __gu_tmp.t; \
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}
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#endif /* !defined(CONFIG_64BIT) */
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#define __put_user_internal(sr, x, ptr) \
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({ \
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ASM_EXCEPTIONTABLE_VAR(__pu_err); \
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__typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x); \
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\
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switch (sizeof(*(ptr))) { \
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case 1: __put_user_asm(sr, "stb", __x, ptr); break; \
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case 2: __put_user_asm(sr, "sth", __x, ptr); break; \
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case 4: __put_user_asm(sr, "stw", __x, ptr); break; \
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case 8: STD_USER(sr, __x, ptr); break; \
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default: BUILD_BUG(); \
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} \
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\
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__pu_err; \
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})
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#define __put_user(x, ptr) \
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({ \
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__put_user_internal("%%sr3,", x, ptr); \
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})
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#define __put_kernel_nofault(dst, src, type, err_label) \
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{ \
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type __z = *(type *)(src); \
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long __err; \
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__err = __put_user_internal("%%sr0,", __z, (type *)(dst)); \
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if (unlikely(__err)) \
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goto err_label; \
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}
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/*
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* The "__put_user/kernel_asm()" macros tell gcc they read from memory
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* instead of writing. This is because they do not write to any memory
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* gcc knows about, so there are no aliasing issues. These macros must
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* also be aware that fixups are executed in the context of the fault,
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* and any registers used there must be listed as clobbers.
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* The register holding the possible EFAULT error (ASM_EXCEPTIONTABLE_REG)
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* is already listed as input and output register.
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*/
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#define __put_user_asm(sr, stx, x, ptr) \
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__asm__ __volatile__ ( \
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"1: " stx " %2,0(" sr "%1)\n" \
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"9:\n" \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
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: "=r"(__pu_err) \
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: "r"(ptr), "r"(x), "0"(__pu_err))
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#if !defined(CONFIG_64BIT)
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#define __put_user_asm64(sr, __val, ptr) do { \
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__asm__ __volatile__ ( \
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"1: stw %2,0(" sr "%1)\n" \
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"2: stw %R2,4(" sr "%1)\n" \
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"9:\n" \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
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ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
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: "=r"(__pu_err) \
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: "r"(ptr), "r"(__val), "0"(__pu_err)); \
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} while (0)
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#endif /* !defined(CONFIG_64BIT) */
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/*
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* Complex access routines -- external declarations
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*/
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extern long strncpy_from_user(char *, const char __user *, long);
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extern __must_check unsigned lclear_user(void __user *, unsigned long);
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extern __must_check long strnlen_user(const char __user *src, long n);
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/*
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* Complex access routines -- macros
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*/
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#define clear_user lclear_user
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#define __clear_user lclear_user
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unsigned long __must_check raw_copy_to_user(void __user *dst, const void *src,
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unsigned long len);
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unsigned long __must_check raw_copy_from_user(void *dst, const void __user *src,
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unsigned long len);
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#define INLINE_COPY_TO_USER
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#define INLINE_COPY_FROM_USER
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struct pt_regs;
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int fixup_exception(struct pt_regs *regs);
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#endif /* __PARISC_UACCESS_H */
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