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riscv: remove address space overrides using set_fs()

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Stop providing the possibility to override the address space using
set_fs() now that there is no need for that any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Christoph Hellwig 2020-09-07 07:58:25 +02:00 committed by Palmer Dabbelt
parent d464118cdc
commit e8d444d3e9
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
4 changed files with 1 additions and 34 deletions
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1
arch/riscv/Kconfig
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@ -87,7 +87,6 @@ config RISCV
select SPARSE_IRQ select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK select THREAD_INFO_IN_TASK
select SET_FS
select UACCESS_MEMCPY if !MMU select UACCESS_MEMCPY if !MMU
config ARCH_MMAP_RND_BITS_MIN config ARCH_MMAP_RND_BITS_MIN

6
arch/riscv/include/asm/thread_info.h
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@ -24,10 +24,6 @@
#include <asm/processor.h> #include <asm/processor.h>
#include <asm/csr.h> #include <asm/csr.h>
typedef struct {
unsigned long seg;
} mm_segment_t;
/* /*
* low level task data that entry.S needs immediate access to * low level task data that entry.S needs immediate access to
* - this struct should fit entirely inside of one cache line * - this struct should fit entirely inside of one cache line
@ -39,7 +35,6 @@ typedef struct {
struct thread_info { struct thread_info {
unsigned long flags; /* low level flags */ unsigned long flags; /* low level flags */
int preempt_count; /* 0=>preemptible, <0=>BUG */ int preempt_count; /* 0=>preemptible, <0=>BUG */
mm_segment_t addr_limit;
/* /*
* These stack pointers are overwritten on every system call or * These stack pointers are overwritten on every system call or
* exception. SP is also saved to the stack it can be recovered when * exception. SP is also saved to the stack it can be recovered when
@ -59,7 +54,6 @@ struct thread_info {
{ \ { \
.flags = 0, \ .flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \ .preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
} }
#endif /* !__ASSEMBLY__ */ #endif /* !__ASSEMBLY__ */

27
arch/riscv/include/asm/uaccess.h
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@ -26,29 +26,6 @@
#define __disable_user_access() \ #define __disable_user_access() \
__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory") __asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
/*
* 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.
*/
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define KERNEL_DS MAKE_MM_SEG(~0UL)
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
}
#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
#define user_addr_max() (get_fs().seg)
/** /**
* access_ok: - Checks if a user space pointer is valid * access_ok: - Checks if a user space pointer is valid
* @addr: User space pointer to start of block to check * @addr: User space pointer to start of block to check
@ -76,9 +53,7 @@ static inline void set_fs(mm_segment_t fs)
*/ */
static inline int __access_ok(unsigned long addr, unsigned long size) static inline int __access_ok(unsigned long addr, unsigned long size)
{ {
const mm_segment_t fs = get_fs(); return size <= TASK_SIZE && addr <= TASK_SIZE - size;
return size <= fs.seg && addr <= fs.seg - size;
} }
/* /*

1
arch/riscv/kernel/process.c
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@ -84,7 +84,6 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
} }
regs->epc = pc; regs->epc = pc;
regs->sp = sp; regs->sp = sp;
set_fs(USER_DS);
} }
void flush_thread(void) void flush_thread(void)