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| author | Max Filippov <jcmvbkbc@gmail.com> | 2019-12-10 14:23:49 -0800 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2022-05-01 19:51:21 -0700 |
| commit | a8f0c31fa87dcf9154c4209960f1dd1ed6a1aad8 (patch) | |
| tree | d32478a51694a14cbd5c80e6768ea0869647aa88 /arch/xtensa/mm | |
| parent | 270a8306917e40746a02494abbd40828356b08e1 (diff) | |
| download | linux-a8f0c31fa87dcf9154c4209960f1dd1ed6a1aad8.tar.bz2 | |
xtensa: noMMU: allow handling protection faults
Many xtensa CPU cores without full MMU still have memory protection
features capable of raising exceptions for invalid instruction
fetches/data access. Allow handling such exceptions. This improves
behavior of processes that pass invalid memory pointers to syscalls in
noMMU configs: in case of exception the kernel instead of killing the
process is now able to return -EINVAL from a syscall.
Introduce CONFIG_PFAULT that controls whether protection fault code is
enabled and register handlers for common memory protection exceptions
when it is enabled.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/mm')
| -rw-r--r-- | arch/xtensa/mm/Makefile | 3 | ||||
| -rw-r--r-- | arch/xtensa/mm/fault.c | 4 |
2 files changed, 6 insertions, 1 deletions
diff --git a/arch/xtensa/mm/Makefile b/arch/xtensa/mm/Makefile index f7fb08ae768f..44153a335951 100644 --- a/arch/xtensa/mm/Makefile +++ b/arch/xtensa/mm/Makefile @@ -4,7 +4,8 @@ # obj-y := init.o misc.o -obj-$(CONFIG_MMU) += cache.o fault.o ioremap.o mmu.o tlb.o +obj-$(CONFIG_PFAULT) += fault.o +obj-$(CONFIG_MMU) += cache.o ioremap.o mmu.o tlb.o obj-$(CONFIG_HIGHMEM) += highmem.o obj-$(CONFIG_KASAN) += kasan_init.o diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index 01e66da4a6b0..16f0a5ff5799 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -25,6 +25,7 @@ void bad_page_fault(struct pt_regs*, unsigned long, int); static void vmalloc_fault(struct pt_regs *regs, unsigned int address) { +#ifdef CONFIG_MMU /* Synchronize this task's top level page-table * with the 'reference' page table. */ @@ -71,6 +72,9 @@ static void vmalloc_fault(struct pt_regs *regs, unsigned int address) bad_page_fault: bad_page_fault(regs, address, SIGKILL); +#else + WARN_ONCE(1, "%s in noMMU configuration\n", __func__); +#endif } /* * This routine handles page faults. It determines the address, |