diff options
Diffstat (limited to 'arch/arm64/include/asm/uaccess.h')
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 115 |
1 files changed, 103 insertions, 12 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 55d0adbf6509..5308d696311b 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -18,6 +18,10 @@ #ifndef __ASM_UACCESS_H #define __ASM_UACCESS_H +#include <asm/alternative.h> +#include <asm/kernel-pgtable.h> +#include <asm/sysreg.h> + /* * User space memory access functions */ @@ -26,10 +30,8 @@ #include <linux/string.h> #include <linux/thread_info.h> -#include <asm/alternative.h> #include <asm/cpufeature.h> #include <asm/ptrace.h> -#include <asm/sysreg.h> #include <asm/errno.h> #include <asm/memory.h> #include <asm/compiler.h> @@ -120,6 +122,99 @@ static inline void set_fs(mm_segment_t fs) " .popsection\n" /* + * User access enabling/disabling. + */ +#ifdef CONFIG_ARM64_SW_TTBR0_PAN +static inline void __uaccess_ttbr0_disable(void) +{ + unsigned long ttbr; + + /* reserved_ttbr0 placed at the end of swapper_pg_dir */ + ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; + write_sysreg(ttbr, ttbr0_el1); + isb(); +} + +static inline void __uaccess_ttbr0_enable(void) +{ + unsigned long flags; + + /* + * Disable interrupts to avoid preemption between reading the 'ttbr0' + * variable and the MSR. A context switch could trigger an ASID + * roll-over and an update of 'ttbr0'. + */ + local_irq_save(flags); + write_sysreg(current_thread_info()->ttbr0, ttbr0_el1); + isb(); + local_irq_restore(flags); +} + +static inline bool uaccess_ttbr0_disable(void) +{ + if (!system_uses_ttbr0_pan()) + return false; + __uaccess_ttbr0_disable(); + return true; +} + +static inline bool uaccess_ttbr0_enable(void) +{ + if (!system_uses_ttbr0_pan()) + return false; + __uaccess_ttbr0_enable(); + return true; +} +#else +static inline bool uaccess_ttbr0_disable(void) +{ + return false; +} + +static inline bool uaccess_ttbr0_enable(void) +{ + return false; +} +#endif + +#define __uaccess_disable(alt) \ +do { \ + if (!uaccess_ttbr0_disable()) \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \ + CONFIG_ARM64_PAN)); \ +} while (0) + +#define __uaccess_enable(alt) \ +do { \ + if (!uaccess_ttbr0_enable()) \ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \ + CONFIG_ARM64_PAN)); \ +} while (0) + +static inline void uaccess_disable(void) +{ + __uaccess_disable(ARM64_HAS_PAN); +} + +static inline void uaccess_enable(void) +{ + __uaccess_enable(ARM64_HAS_PAN); +} + +/* + * These functions are no-ops when UAO is present. + */ +static inline void uaccess_disable_not_uao(void) +{ + __uaccess_disable(ARM64_ALT_PAN_NOT_UAO); +} + +static inline void uaccess_enable_not_uao(void) +{ + __uaccess_enable(ARM64_ALT_PAN_NOT_UAO); +} + +/* * The "__xxx" versions of the user access functions do not verify the address * space - it must have been done previously with a separate "access_ok()" * call. @@ -146,8 +241,7 @@ static inline void set_fs(mm_segment_t fs) do { \ unsigned long __gu_val; \ __chk_user_ptr(ptr); \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\ - CONFIG_ARM64_PAN)); \ + uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \ @@ -168,9 +262,8 @@ do { \ default: \ BUILD_BUG(); \ } \ + uaccess_disable_not_uao(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\ - CONFIG_ARM64_PAN)); \ } while (0) #define __get_user(x, ptr) \ @@ -215,8 +308,7 @@ do { \ do { \ __typeof__(*(ptr)) __pu_val = (x); \ __chk_user_ptr(ptr); \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\ - CONFIG_ARM64_PAN)); \ + uaccess_enable_not_uao(); \ switch (sizeof(*(ptr))) { \ case 1: \ __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \ @@ -237,8 +329,7 @@ do { \ default: \ BUILD_BUG(); \ } \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\ - CONFIG_ARM64_PAN)); \ + uaccess_disable_not_uao(); \ } while (0) #define __put_user(x, ptr) \ @@ -288,9 +379,9 @@ static inline unsigned long __must_check copy_from_user(void *to, const void __u { unsigned long res = n; kasan_check_write(to, n); + check_object_size(to, n, false); if (access_ok(VERIFY_READ, from, n)) { - check_object_size(to, n, false); res = __arch_copy_from_user(to, from, n); } if (unlikely(res)) @@ -301,9 +392,9 @@ static inline unsigned long __must_check copy_from_user(void *to, const void __u static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) { kasan_check_read(from, n); + check_object_size(from, n, true); if (access_ok(VERIFY_WRITE, to, n)) { - check_object_size(from, n, true); n = __arch_copy_to_user(to, from, n); } return n; |
