[PATCH 6.3 19/29] mm/fault: convert remaining simple cases to lock_mm_and_find_vma()

Greg Kroah-Hartman
2023-06-29T18:46:38Z

From: Linus Torvalds <torvalds@linux-foundation.org>

commit a050ba1e7422f2cc60ff8bfde3f96d34d00cb585 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/alpha/Kconfig | 1 +
arch/alpha/mm/fault.c | 13 +++----------
arch/arc/Kconfig | 1 +
arch/arc/mm/fault.c | 11 +++--------
arch/csky/Kconfig | 1 +
arch/csky/mm/fault.c | 22 +++++-----------------
arch/hexagon/Kconfig | 1 +
arch/hexagon/mm/vm_fault.c | 18 ++++--------------
arch/loongarch/Kconfig | 1 +
arch/loongarch/mm/fault.c | 16 ++++++----------
arch/nios2/Kconfig | 1 +
arch/nios2/mm/fault.c | 17 ++---------------
arch/sh/Kconfig | 1 +
arch/sh/mm/fault.c | 17 ++---------------
arch/sparc/Kconfig | 1 +
arch/sparc/mm/fault_32.c | 32 ++++++++------------------------
arch/xtensa/Kconfig | 1 +
arch/xtensa/mm/fault.c | 14 +++-----------
18 files changed, 45 insertions(+), 124 deletions(-)

--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -29,6 +29,7 @@ config ALPHA
select GENERIC_SMP_IDLE_THREAD
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
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -119,20 +119,12 @@ do_page_fault(unsigned long address, uns
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;

--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -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
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -113,15 +113,9 @@ void do_page_fault(unsigned long address

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)
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -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
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -97,13 +97,12 @@ static inline void mm_fault_error(struct
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_
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;
}

--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -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
--- a/arch/hexagon/mm/vm_fault.c
+++ b/arch/hexagon/mm/vm_fault.c
@@ -57,21 +57,10 @@ void do_page_fault(unsigned long address

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;
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -125,6 +125,7 @@ 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
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -169,22 +169,18 @@ static void __kprobes __do_page_fault(st

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))
- goto good_area;
+ 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;

--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -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
--- a/arch/nios2/mm/fault.c
+++ b/arch/nios2/mm/fault.c
@@ -86,27 +86,14 @@ asmlinkage void do_page_fault(struct pt_

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) {
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -56,6 +56,7 @@ 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
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -439,21 +439,9 @@ asmlinkage void __kprobes do_page_fault(
}

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;
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -56,6 +56,7 @@ config SPARC32
select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64
select HAVE_UID16
+ select LOCK_MM_AND_FIND_VMA
select OLD_SIGACTION
select ZONE_DMA

--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -143,28 +143,19 @@ asmlinkage void do_sparc_fault(struct pt
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 lo

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;

--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -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
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -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;