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mm/fault: convert remaining simple cases to lock_mm_and_find_vma()

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This does the simple pattern conversion of alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa to the lock_mm_and_find_vma()
helper.  They all have the regular fault handling pattern without odd
special cases.

The remaining architectures all have something that keeps us from a
straightforward conversion: ia64 and parisc have stacks that can grow
both up as well as down (and ia64 has special address region checks).

And m68k, microblaze, openrisc, sparc64, and um end up having extra
rules about only expanding the stack down a limited amount below the
user space stack pointer.  That is something that x86 used to do too
(long long ago), and it probably could just be skipped, but it still
makes the conversion less than trivial.

Note that this conversion was done manually and with the exception of
alpha without any build testing, because I have a fairly limited cross-
building environment.  The cases are all simple, and I went through the
changes several times, but...

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2023-06-24 10:55:38 -07:00
parent 8b35ca3e45
commit a050ba1e74
18 changed files with 45 additions and 124 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/alpha/Kconfig
View File

@ -30,6 +30,7 @@ config ALPHA
select HAS_IOPORT
select HAVE_ARCH_AUDITSYSCALL
select HAVE_MOD_ARCH_SPECIFIC
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select ODD_RT_SIGACTION
select OLD_SIGSUSPEND

13
arch/alpha/mm/fault.c
View File

@ -119,20 +119,12 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
flags |= FAULT_FLAG_USER;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
goto bad_area_nosemaphore;
/* Ok, we have a good vm_area for this memory access, so
we can handle it. */
good_area:
si_code = SEGV_ACCERR;
if (cause < 0) {
if (!(vma->vm_flags & VM_EXEC))
@ -192,6 +184,7 @@ retry:
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
if (user_mode(regs))
goto do_sigsegv;

1
arch/arc/Kconfig
View File

@ -41,6 +41,7 @@ config ARC
select HAVE_PERF_EVENTS
select HAVE_SYSCALL_TRACEPOINTS
select IRQ_DOMAIN
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select OF
select OF_EARLY_FLATTREE

11
arch/arc/mm/fault.c
View File

@ -113,15 +113,9 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (unlikely(address < vma->vm_start)) {
if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address))
goto bad_area;
}
goto bad_area_nosemaphore;
/*
* vm_area is good, now check permissions for this memory access
@ -161,6 +155,7 @@ retry:
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
/*
* Major/minor page fault accounting
* (in case of retry we only land here once)

1
arch/csky/Kconfig
View File

@ -96,6 +96,7 @@ config CSKY
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select LOCK_MM_AND_FIND_VMA
select MAY_HAVE_SPARSE_IRQ
select MODULES_USE_ELF_RELA if MODULES
select OF

22
arch/csky/mm/fault.c
View File

@ -97,13 +97,12 @@ static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_f
BUG();
}
static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code, unsigned long addr)
static inline void bad_area_nosemaphore(struct pt_regs *regs, struct mm_struct *mm, int code, unsigned long addr)
{
/*
* Something tried to access memory that isn't in our memory map.
* Fix it, but check if it's kernel or user first.
*/
mmap_read_unlock(mm);
/* User mode accesses just cause a SIGSEGV */
if (user_mode(regs)) {
do_trap(regs, SIGSEGV, code, addr);
@ -238,20 +237,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
if (is_write(regs))
flags |= FAULT_FLAG_WRITE;
retry:
mmap_read_lock(mm);
vma = find_vma(mm, addr);
vma = lock_mm_and_find_vma(mm, address, regs);
if (unlikely(!vma)) {
bad_area(regs, mm, code, addr);
return;
}
if (likely(vma->vm_start <= addr))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
bad_area(regs, mm, code, addr);
return;
}
if (unlikely(expand_stack(vma, addr))) {
bad_area(regs, mm, code, addr);
bad_area_nosemaphore(regs, mm, code, addr);
return;
}
@ -259,11 +247,11 @@ retry:
* Ok, we have a good vm_area for this memory access, so
* we can handle it.
*/
good_area:
code = SEGV_ACCERR;
if (unlikely(access_error(regs, vma))) {
bad_area(regs, mm, code, addr);
mmap_read_unlock(mm);
bad_area_nosemaphore(regs, mm, code, addr);
return;
}

1
arch/hexagon/Kconfig
View File

@ -28,6 +28,7 @@ config HEXAGON
select GENERIC_SMP_IDLE_THREAD
select STACKTRACE_SUPPORT
select GENERIC_CLOCKEVENTS_BROADCAST
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select GENERIC_CPU_DEVICES
select ARCH_WANT_LD_ORPHAN_WARN

18
arch/hexagon/mm/vm_fault.c
View File

@ -57,21 +57,10 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
vma = lock_mm_and_find_vma(mm, address, regs);
if (unlikely(!vma))
goto bad_area_nosemaphore;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
good_area:
/* Address space is OK. Now check access rights. */
si_code = SEGV_ACCERR;
@ -143,6 +132,7 @@ good_area:
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
if (user_mode(regs)) {
force_sig_fault(SIGSEGV, si_code, (void __user *)address);
return;

1
arch/loongarch/Kconfig
View File

@ -130,6 +130,7 @@ config LOONGARCH
select HAVE_VIRT_CPU_ACCOUNTING_GEN if !SMP
select IRQ_FORCED_THREADING
select IRQ_LOONGARCH_CPU
select LOCK_MM_AND_FIND_VMA
select MMU_GATHER_MERGE_VMAS if MMU
select MODULES_USE_ELF_RELA if MODULES
select NEED_PER_CPU_EMBED_FIRST_CHUNK

14
arch/loongarch/mm/fault.c
View File

@ -169,22 +169,18 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (!expand_stack(vma, address))
vma = lock_mm_and_find_vma(mm, address, regs);
if (unlikely(!vma))
goto bad_area_nosemaphore;
goto good_area;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
do_sigsegv(regs, write, address, si_code);
return;

1
arch/nios2/Kconfig
View File

@ -16,6 +16,7 @@ config NIOS2
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_KGDB
select IRQ_DOMAIN
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select OF
select OF_EARLY_FLATTREE

17
arch/nios2/mm/fault.c
View File

@ -86,27 +86,14 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
if (!mmap_read_trylock(mm)) {
if (!user_mode(regs) && !search_exception_tables(regs->ea))
goto bad_area_nosemaphore;
retry:
mmap_read_lock(mm);
}
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
goto bad_area_nosemaphore;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
code = SEGV_ACCERR;
switch (cause) {

1
arch/sh/Kconfig
View File

@ -59,6 +59,7 @@ config SUPERH
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select IRQ_FORCED_THREADING
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select NEED_SG_DMA_LENGTH
select NO_DMA if !MMU && !DMA_COHERENT

17
arch/sh/mm/fault.c
View File

@ -439,21 +439,9 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
}
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (unlikely(!vma)) {
bad_area(regs, error_code, address);
return;
}
if (likely(vma->vm_start <= address))
goto good_area;
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
bad_area(regs, error_code, address);
return;
}
if (unlikely(expand_stack(vma, address))) {
bad_area(regs, error_code, address);
bad_area_nosemaphore(regs, error_code, address);
return;
}
@ -461,7 +449,6 @@ retry:
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
if (unlikely(access_error(error_code, vma))) {
bad_area_access_error(regs, error_code, address);
return;

1
arch/sparc/Kconfig
View File

@ -57,6 +57,7 @@ config SPARC32
select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64
select HAVE_UID16
select LOCK_MM_AND_FIND_VMA
select OLD_SIGACTION
select ZONE_DMA

32
arch/sparc/mm/fault_32.c
View File

@ -143,28 +143,19 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
if (pagefault_disabled() || !mm)
goto no_context;
if (!from_user && address >= PAGE_OFFSET)
goto no_context;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
if (!from_user && address >= PAGE_OFFSET)
goto bad_area;
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
goto bad_area_nosemaphore;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
code = SEGV_ACCERR;
if (write) {
if (!(vma->vm_flags & VM_WRITE))
@ -321,17 +312,9 @@ static void force_user_fault(unsigned long address, int write)
code = SEGV_MAPERR;
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
good_area:
goto bad_area_nosemaphore;
code = SEGV_ACCERR;
if (write) {
if (!(vma->vm_flags & VM_WRITE))
@ -350,6 +333,7 @@ good_area:
return;
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
return;

1
arch/xtensa/Kconfig
View File

@ -49,6 +49,7 @@ config XTENSA
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING_GEN
select IRQ_DOMAIN
select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA
select PERF_USE_VMALLOC
select TRACE_IRQFLAGS_SUPPORT

14
arch/xtensa/mm/fault.c
View File

@ -130,23 +130,14 @@ void do_page_fault(struct pt_regs *regs)
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
retry:
mmap_read_lock(mm);
vma = find_vma(mm, address);
vma = lock_mm_and_find_vma(mm, address, regs);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
goto bad_area_nosemaphore;
/* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
code = SEGV_ACCERR;
if (is_write) {
@ -205,6 +196,7 @@ good_area:
*/
bad_area:
mmap_read_unlock(mm);
bad_area_nosemaphore:
if (user_mode(regs)) {
force_sig_fault(SIGSEGV, code, (void *) address);
return;