diff options
| -rw-r--r-- | arch/arm64/include/asm/asm-extable.h | 10 | ||||
| -rw-r--r-- | arch/arm64/include/asm/extable.h | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/extable.c | 25 | ||||
| -rw-r--r-- | arch/arm64/mm/fault.c | 2 |
4 files changed, 35 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h index b8a5861dc7b7..292f2687a12e 100644 --- a/arch/arm64/include/asm/asm-extable.h +++ b/arch/arm64/include/asm/asm-extable.h @@ -9,7 +9,8 @@ #define EX_TYPE_BPF 1 #define EX_TYPE_UACCESS_ERR_ZERO 2 #define EX_TYPE_KACCESS_ERR_ZERO 3 -#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4 +#define EX_TYPE_UACCESS_CPY 4 +#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 5 /* Data fields for EX_TYPE_UACCESS_ERR_ZERO */ #define EX_DATA_REG_ERR_SHIFT 0 @@ -23,6 +24,9 @@ #define EX_DATA_REG_ADDR_SHIFT 5 #define EX_DATA_REG_ADDR GENMASK(9, 5) +/* Data fields for EX_TYPE_UACCESS_CPY */ +#define EX_DATA_UACCESS_WRITE BIT(0) + #ifdef __ASSEMBLY__ #define __ASM_EXTABLE_RAW(insn, fixup, type, data) \ @@ -69,6 +73,10 @@ .endif .endm + .macro _asm_extable_uaccess_cpy, insn, fixup, uaccess_is_write + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_CPY, \uaccess_is_write) + .endm + #else /* __ASSEMBLY__ */ #include <linux/stringify.h> diff --git a/arch/arm64/include/asm/extable.h b/arch/arm64/include/asm/extable.h index 72b0e71cc3de..5892b8977710 100644 --- a/arch/arm64/include/asm/extable.h +++ b/arch/arm64/include/asm/extable.h @@ -45,5 +45,5 @@ bool ex_handler_bpf(const struct exception_table_entry *ex, } #endif /* !CONFIG_BPF_JIT */ -bool fixup_exception(struct pt_regs *regs); +bool fixup_exception(struct pt_regs *regs, unsigned long esr); #endif diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c index 228d681a8715..afb5241e4d91 100644 --- a/arch/arm64/mm/extable.c +++ b/arch/arm64/mm/extable.c @@ -8,8 +8,18 @@ #include <linux/uaccess.h> #include <asm/asm-extable.h> +#include <asm/esr.h> #include <asm/ptrace.h> +static bool cpy_faulted_on_uaccess(const struct exception_table_entry *ex, + unsigned long esr) +{ + bool uaccess_is_write = FIELD_GET(EX_DATA_UACCESS_WRITE, ex->data); + bool fault_on_write = esr & ESR_ELx_WNR; + + return uaccess_is_write == fault_on_write; +} + static inline unsigned long get_ex_fixup(const struct exception_table_entry *ex) { @@ -29,6 +39,17 @@ static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex, return true; } +static bool ex_handler_uaccess_cpy(const struct exception_table_entry *ex, + struct pt_regs *regs, unsigned long esr) +{ + /* Do not fix up faults on kernel memory accesses */ + if (!cpy_faulted_on_uaccess(ex, esr)) + return false; + + regs->pc = get_ex_fixup(ex); + return true; +} + static bool ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex, struct pt_regs *regs) @@ -56,7 +77,7 @@ ex_handler_load_unaligned_zeropad(const struct exception_table_entry *ex, return true; } -bool fixup_exception(struct pt_regs *regs) +bool fixup_exception(struct pt_regs *regs, unsigned long esr) { const struct exception_table_entry *ex; @@ -70,6 +91,8 @@ bool fixup_exception(struct pt_regs *regs) case EX_TYPE_UACCESS_ERR_ZERO: case EX_TYPE_KACCESS_ERR_ZERO: return ex_handler_uaccess_err_zero(ex, regs); + case EX_TYPE_UACCESS_CPY: + return ex_handler_uaccess_cpy(ex, regs, esr); case EX_TYPE_LOAD_UNALIGNED_ZEROPAD: return ex_handler_load_unaligned_zeropad(ex, regs); } diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index ef63651099a9..da4854fc6150 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -375,7 +375,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned long esr, * Are we prepared to handle this kernel fault? * We are almost certainly not prepared to handle instruction faults. */ - if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) + if (!is_el1_instruction_abort(esr) && fixup_exception(regs, esr)) return; if (WARN_RATELIMIT(is_spurious_el1_translation_fault(addr, esr, regs), |