[PATCH 6.1 19/30] riscv/mm: Convert to using lock_mm_and_find_vma()

Greg Kroah-Hartman
2023-06-29T18:45:05Z

From: Ben Hutchings <ben@decadent.org.uk>

commit 7267ef7b0b77f4ed23b7b3c87d8eca7bd9c2d007 upstream.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[6.1: Kconfig context]
Signed-off-by: Samuel Mendoza-Jonas <samjonas@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/riscv/Kconfig | 1 +
arch/riscv/mm/fault.c | 31 +++++++++++++------------------
2 files changed, 14 insertions(+), 18 deletions(-)

--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -114,6 +114,7 @@ config RISCV
select HAVE_RSEQ
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
+ select LOCK_MM_AND_FIND_VMA
select MODULES_USE_ELF_RELA if MODULES
select MODULE_SECTIONS if MODULES
select OF
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -83,13 +83,13 @@ 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, 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);
@@ -99,6 +99,15 @@ static inline void bad_area(struct pt_re
no_context(regs, addr);
}

+static inline void
+bad_area(struct pt_regs *regs, struct mm_struct *mm, int code,
+ unsigned long addr)
+{
+ mmap_read_unlock(mm);
+
+ bad_area_nosemaphore(regs, code, addr);
+}
+
static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
{
pgd_t *pgd, *pgd_k;
@@ -281,23 +290,10 @@ asmlinkage void do_page_fault(struct pt_
else if (cause == EXC_INST_PAGE_FAULT)
flags |= FAULT_FLAG_INSTRUCTION;
retry:
- mmap_read_lock(mm);
- vma = find_vma(mm, addr);
+ vma = lock_mm_and_find_vma(mm, addr, regs);
if (unlikely(!vma)) {
tsk->thread.bad_cause = cause;
- bad_area(regs, mm, code, addr);
- return;
- }
- if (likely(vma->vm_start <= addr))
- goto good_area;
- if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
- tsk->thread.bad_cause = cause;
- bad_area(regs, mm, code, addr);
- return;
- }
- if (unlikely(expand_stack(vma, addr))) {
- tsk->thread.bad_cause = cause;
- bad_area(regs, mm, code, addr);
+ bad_area_nosemaphore(regs, code, addr);
return;
}

@@ -305,7 +301,6 @@ 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(cause, vma))) {