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| author | Max Filippov <jcmvbkbc@gmail.com> | 2019-12-11 01:23:49 +0300 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2022-05-02 05:51:21 +0300 |
| commit | a8f0c31fa87dcf9154c4209960f1dd1ed6a1aad8 (patch) | |
| tree | d32478a51694a14cbd5c80e6768ea0869647aa88 /arch | |
| parent | 270a8306917e40746a02494abbd40828356b08e1 (diff) | |
| download | linux-a8f0c31fa87dcf9154c4209960f1dd1ed6a1aad8.tar.xz | |
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')
| -rw-r--r-- | arch/xtensa/Kconfig | 11 | ||||
| -rw-r--r-- | arch/xtensa/kernel/traps.c | 20 | ||||
| -rw-r--r-- | arch/xtensa/mm/Makefile | 3 | ||||
| -rw-r--r-- | arch/xtensa/mm/fault.c | 4 |
4 files changed, 27 insertions, 11 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index bd113bc6e192..bca2763495a1 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -79,6 +79,7 @@ config STACKTRACE_SUPPORT config MMU def_bool n + select PFAULT config HAVE_XTENSA_GPIO32 def_bool n @@ -178,6 +179,16 @@ config XTENSA_FAKE_NMI If unsure, say N. +config PFAULT + bool "Handle protection faults" if EXPERT && !MMU + default y + help + Handle protection faults. MMU configurations must enable it. + noMMU configurations may disable it if used memory map never + generates protection faults or faults are always fatal. + + If unsure, say Y. + config XTENSA_UNALIGNED_USER bool "Unaligned memory access in user space" help diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 9345007d474d..82ced7b25b77 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -110,21 +110,21 @@ static dispatch_init_table_t __initdata dispatch_init_table[] = { { EXCCAUSE_UNALIGNED, KRNL, fast_unaligned }, #endif #ifdef CONFIG_MMU -{ EXCCAUSE_ITLB_MISS, 0, do_page_fault }, -{ EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, +{ EXCCAUSE_ITLB_MISS, 0, do_page_fault }, +{ EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss}, +{ EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, +{ EXCCAUSE_DTLB_MISS, 0, do_page_fault }, +{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, +#endif /* CONFIG_MMU */ +#ifdef CONFIG_PFAULT { EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit }, -{ EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, -/* EXCCAUSE_SIZE_RESTRICTION unhandled */ +{ EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault }, { EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault }, -{ EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss}, -{ EXCCAUSE_DTLB_MISS, 0, do_page_fault }, { EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit }, -{ EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, -/* EXCCAUSE_DTLB_SIZE_RESTRICTION unhandled */ -{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited }, +{ EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault }, { EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault }, { EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault }, -#endif /* CONFIG_MMU */ +#endif /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */ #if XTENSA_HAVE_COPROCESSOR(0) COPROCESSOR(0), 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, |