cregit-Linux how code gets into the kernel

Release 4.18 arch/powerpc/include/asm/uaccess.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ARCH_POWERPC_UACCESS_H

#define _ARCH_POWERPC_UACCESS_H

#include <asm/asm-compat.h>
#include <asm/ppc_asm.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/extable.h>

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 *
 * The fs/ds values are now the highest legal address in the "segment".
 * This simplifies the checking in the routines below.
 */


#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })


#define KERNEL_DS	MAKE_MM_SEG(~0UL)
#ifdef __powerpc64__
/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */

#define USER_DS		MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
#else

#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
#endif


#define get_ds()	(KERNEL_DS)

#define get_fs()	(current->thread.addr_limit)


static inline void set_fs(mm_segment_t fs) { current->thread.addr_limit = fs; /* On user-mode return check addr_limit (fs) is correct */ set_thread_flag(TIF_FSCHECK); }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman2187.50%150.00%
Anton Blanchard312.50%150.00%
Total24100.00%2100.00%

#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 * gap between user addresses and the kernel addresses */ #define __access_ok(addr, size, segment) \ (((addr) <= (segment).seg) && ((size) <= (segment).seg)) #else
static inline int __access_ok(unsigned long addr, unsigned long size, mm_segment_t seg) { if (addr > seg.seg) return 0; return (size == 0 || size - 1 <= seg.seg - addr); }

Contributors

PersonTokensPropCommitsCommitProp
Mathieu Malaterre3984.78%150.00%
Stephen Rothwell715.22%150.00%
Total46100.00%2100.00%

#endif #define access_ok(type, addr, size) \ (__chk_user_ptr(addr), \ __access_ok((__force unsigned long)(addr), (size), get_fs())) /* * These are the main single-value transfer routines. They automatically * use the right size if we just have the right pointer type. * * This gets kind of ugly. We want to return _two_ values in "get_user()" * and yet we don't want to do any pointers, because that is too much * of a performance impact. Thus we have a few rather ugly macros here, * and hide all the ugliness from the user. * * The "__xxx" versions of the user access functions are versions that * do not verify the address space, that must have been done previously * with a separate "access_ok()" call (this is used when we do multiple * accesses to the same area of user memory). * * As we use the same address space for kernel and user data on the * PowerPC, we can just do these as direct assignments. (Of course, the * exception handling means that it's no longer "just"...) * */ #define get_user(x, ptr) \ __get_user_check((x), (ptr), sizeof(*(ptr))) #define put_user(x, ptr) \ __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) #define __get_user(x, ptr) \ __get_user_nocheck((x), (ptr), sizeof(*(ptr))) #define __put_user(x, ptr) \ __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) #define __get_user_inatomic(x, ptr) \ __get_user_nosleep((x), (ptr), sizeof(*(ptr))) #define __put_user_inatomic(x, ptr) \ __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) extern long __put_user_bad(void); /* * We don't tell gcc that we are accessing memory, but this is OK * because we do not write to any memory gcc knows about, so there * are no aliasing issues. */ #define __put_user_asm(x, addr, err, op) \ __asm__ __volatile__( \ "1: " op " %1,0(%2) # put_user\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: li %0,%3\n" \ " b 2b\n" \ ".previous\n" \ EX_TABLE(1b, 3b) \ : "=r" (err) \ : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err)) #ifdef __powerpc64__ #define __put_user_asm2(x, ptr, retval) \ __put_user_asm(x, ptr, retval, "std") #else /* __powerpc64__ */ #define __put_user_asm2(x, addr, err) \ __asm__ __volatile__( \ "1: stw %1,0(%2)\n" \ "2: stw %1+1,4(%2)\n" \ "3:\n" \ ".section .fixup,\"ax\"\n" \ "4: li %0,%3\n" \ " b 3b\n" \ ".previous\n" \ EX_TABLE(1b, 4b) \ EX_TABLE(2b, 4b) \ : "=r" (err) \ : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err)) #endif /* __powerpc64__ */ #define __put_user_size(x, ptr, size, retval) \ do { \ retval = 0; \ switch (size) { \ case 1: __put_user_asm(x, ptr, retval, "stb"); break; \ case 2: __put_user_asm(x, ptr, retval, "sth"); break; \ case 4: __put_user_asm(x, ptr, retval, "stw"); break; \ case 8: __put_user_asm2(x, ptr, retval); break; \ default: __put_user_bad(); \ } \ } while (0) #define __put_user_nocheck(x, ptr, size) \ ({ \ long __pu_err; \ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ if (!is_kernel_addr((unsigned long)__pu_addr)) \ might_fault(); \ __chk_user_ptr(ptr); \ __put_user_size((x), __pu_addr, (size), __pu_err); \ __pu_err; \ }) #define __put_user_check(x, ptr, size) \ ({ \ long __pu_err = -EFAULT; \ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ might_fault(); \ if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ __put_user_size((x), __pu_addr, (size), __pu_err); \ __pu_err; \ }) #define __put_user_nosleep(x, ptr, size) \ ({ \ long __pu_err; \ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ __chk_user_ptr(ptr); \ __put_user_size((x), __pu_addr, (size), __pu_err); \ __pu_err; \ }) extern long __get_user_bad(void); /* * This does an atomic 128 byte aligned load from userspace. * Upto caller to do enable_kernel_vmx() before calling! */ #define __get_user_atomic_128_aligned(kaddr, uaddr, err) \ __asm__ __volatile__( \ "1: lvx 0,0,%1 # get user\n" \ " stvx 0,0,%2 # put kernel\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: li %0,%3\n" \ " b 2b\n" \ ".previous\n" \ EX_TABLE(1b, 3b) \ : "=r" (err) \ : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err)) #define __get_user_asm(x, addr, err, op) \ __asm__ __volatile__( \ "1: "op" %1,0(%2) # get_user\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: li %0,%3\n" \ " li %1,0\n" \ " b 2b\n" \ ".previous\n" \ EX_TABLE(1b, 3b) \ : "=r" (err), "=r" (x) \ : "b" (addr), "i" (-EFAULT), "0" (err)) #ifdef __powerpc64__ #define __get_user_asm2(x, addr, err) \ __get_user_asm(x, addr, err, "ld") #else /* __powerpc64__ */ #define __get_user_asm2(x, addr, err) \ __asm__ __volatile__( \ "1: lwz %1,0(%2)\n" \ "2: lwz %1+1,4(%2)\n" \ "3:\n" \ ".section .fixup,\"ax\"\n" \ "4: li %0,%3\n" \ " li %1,0\n" \ " li %1+1,0\n" \ " b 3b\n" \ ".previous\n" \ EX_TABLE(1b, 4b) \ EX_TABLE(2b, 4b) \ : "=r" (err), "=&r" (x) \ : "b" (addr), "i" (-EFAULT), "0" (err)) #endif /* __powerpc64__ */ #define __get_user_size(x, ptr, size, retval) \ do { \ retval = 0; \ __chk_user_ptr(ptr); \ if (size > sizeof(x)) \ (x) = __get_user_bad(); \ switch (size) { \ case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \ case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \ case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \ case 8: __get_user_asm2(x, ptr, retval); break; \ default: (x) = __get_user_bad(); \ } \ } while (0) #define __get_user_nocheck(x, ptr, size) \ ({ \ long __gu_err; \ unsigned long __gu_val; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ if (!is_kernel_addr((unsigned long)__gu_addr)) \ might_fault(); \ barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ (x) = (__typeof__(*(ptr)))__gu_val; \ __gu_err; \ }) #define __get_user_check(x, ptr, size) \ ({ \ long __gu_err = -EFAULT; \ unsigned long __gu_val = 0; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ might_fault(); \ if (access_ok(VERIFY_READ, __gu_addr, (size))) { \ barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ } \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __gu_err; \ }) #define __get_user_nosleep(x, ptr, size) \ ({ \ long __gu_err; \ unsigned long __gu_val; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __gu_err; \ }) /* more complex routines */ extern unsigned long __copy_tofrom_user(void __user *to, const void __user *from, unsigned long size); #ifdef __powerpc64__
static inline unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) { return __copy_tofrom_user(to, from, n); }

Contributors

PersonTokensPropCommitsCommitProp
Stephen Rothwell2987.88%125.00%
Al Viro26.06%125.00%
Kees Cook13.03%125.00%
Adrian Bunk13.03%125.00%
Total33100.00%4100.00%

#endif /* __powerpc64__ */
static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) { if (__builtin_constant_p(n) && (n <= 8)) { unsigned long ret = 1; switch (n) { case 1: barrier_nospec(); __get_user_size(*(u8 *)to, from, 1, ret); break; case 2: barrier_nospec(); __get_user_size(*(u16 *)to, from, 2, ret); break; case 4: barrier_nospec(); __get_user_size(*(u32 *)to, from, 4, ret); break; case 8: barrier_nospec(); __get_user_size(*(u64 *)to, from, 8, ret); break; } if (ret == 0) return 0; } barrier_nospec(); return __copy_tofrom_user((__force void __user *)to, from, n); }

Contributors

PersonTokensPropCommitsCommitProp
Anton Blanchard11970.41%222.22%
Stephen Rothwell2615.38%222.22%
Michael Ellerman158.88%111.11%
Linus Torvalds52.96%111.11%
Nate Case21.18%111.11%
Al Viro21.18%222.22%
Total169100.00%9100.00%


static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) { if (__builtin_constant_p(n) && (n <= 8)) { unsigned long ret = 1; switch (n) { case 1: __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret); break; case 2: __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret); break; case 4: __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret); break; case 8: __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret); break; } if (ret == 0) return 0; } return __copy_tofrom_user(to, (__force const void __user *)from, n); }

Contributors

PersonTokensPropCommitsCommitProp
Anton Blanchard12772.57%330.00%
Stephen Rothwell1810.29%220.00%
Paul Mackerras169.14%110.00%
Linus Torvalds105.71%110.00%
Al Viro21.14%220.00%
Nate Case21.14%110.00%
Total175100.00%10100.00%

extern unsigned long __clear_user(void __user *addr, unsigned long size);
static inline unsigned long clear_user(void __user *addr, unsigned long size) { might_fault(); if (likely(access_ok(VERIFY_WRITE, addr, size))) return __clear_user(addr, size); return size; }

Contributors

PersonTokensPropCommitsCommitProp
Anton Blanchard3680.00%562.50%
Stephen Rothwell715.56%112.50%
Linus Torvalds12.22%112.50%
Michael S. Tsirkin12.22%112.50%
Total45100.00%8100.00%

extern long strncpy_from_user(char *dst, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); extern long __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size); extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset, size_t len); #endif /* _ARCH_POWERPC_UACCESS_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Anton Blanchard51351.40%618.75%
Stephen Rothwell23223.25%39.38%
Michael Ellerman454.51%515.62%
Benjamin Herrenschmidt434.31%13.12%
Mathieu Malaterre393.91%13.12%
Oliver O'Halloran383.81%13.12%
Paul Mackerras292.91%39.38%
Linus Torvalds191.90%13.12%
Michael Neuling131.30%13.12%
Al Viro90.90%39.38%
Nicholas Piggin70.70%13.12%
Nate Case40.40%13.12%
Michael S. Tsirkin30.30%13.12%
Kees Cook10.10%13.12%
Bharat Bhushan10.10%13.12%
Adrian Bunk10.10%13.12%
Greg Kroah-Hartman10.10%13.12%
Total998100.00%32100.00%
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