diff options
| -rw-r--r-- | arch/powerpc/include/asm/book3s/32/kup.h | 103 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/processor.h | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/head_32.S | 11 | ||||
| -rw-r--r-- | arch/powerpc/mm/ppc_mmu_32.c | 10 | ||||
| -rw-r--r-- | arch/powerpc/platforms/Kconfig.cputype | 1 |
6 files changed, 131 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 5f97c742ca71..677e9babef80 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -37,6 +37,109 @@ #endif .endm +#ifdef CONFIG_PPC_KUAP + +.macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */ +101: mtsrin \gpr1, \gpr2 + addi \gpr1, \gpr1, 0x111 /* next VSID */ + rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */ + addis \gpr2, \gpr2, 0x1000 /* address of next segment */ + cmplw \gpr2, \gpr3 + blt- 101b + isync +.endm + +.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3 + lwz \gpr2, KUAP(\thread) + rlwinm. \gpr3, \gpr2, 28, 0xf0000000 + stw \gpr2, STACK_REGS_KUAP(\sp) + beq+ 102f + li \gpr1, 0 + stw \gpr1, KUAP(\thread) + mfsrin \gpr1, \gpr2 + oris \gpr1, \gpr1, SR_KS@h /* set Ks */ + kuap_update_sr \gpr1, \gpr2, \gpr3 +102: +.endm + +.macro kuap_restore sp, current, gpr1, gpr2, gpr3 + lwz \gpr2, STACK_REGS_KUAP(\sp) + rlwinm. \gpr3, \gpr2, 28, 0xf0000000 + stw \gpr2, THREAD + KUAP(\current) + beq+ 102f + mfsrin \gpr1, \gpr2 + rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */ + kuap_update_sr \gpr1, \gpr2, \gpr3 +102: +.endm + +.macro kuap_check current, gpr +#ifdef CONFIG_PPC_KUAP_DEBUG + lwz \gpr2, KUAP(thread) +999: twnei \gpr, 0 + EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) +#endif +.endm + +#endif /* CONFIG_PPC_KUAP */ + +#else /* !__ASSEMBLY__ */ + +#ifdef CONFIG_PPC_KUAP + +#include <linux/sched.h> + +static inline void kuap_update_sr(u32 sr, u32 addr, u32 end) +{ + barrier(); /* make sure thread.kuap is updated before playing with SRs */ + while (addr < end) { + mtsrin(sr, addr); + sr += 0x111; /* next VSID */ + sr &= 0xf0ffffff; /* clear VSID overflow */ + addr += 0x10000000; /* address of next segment */ + } + isync(); /* Context sync required after mtsrin() */ +} + +static inline void allow_user_access(void __user *to, const void __user *from, u32 size) +{ + u32 addr, end; + + if (__builtin_constant_p(to) && to == NULL) + return; + + addr = (__force u32)to; + + if (!addr || addr >= TASK_SIZE || !size) + return; + + end = min(addr + size, TASK_SIZE); + current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); + kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */ +} + +static inline void prevent_user_access(void __user *to, const void __user *from, u32 size) +{ + u32 addr = (__force u32)to; + u32 end = min(addr + size, TASK_SIZE); + + if (!addr || addr >= TASK_SIZE || !size) + return; + + current->thread.kuap = 0; + kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */ +} + +static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write) +{ + if (!is_write) + return false; + + return WARN(!regs->kuap, "Bug: write fault blocked by segment registers !"); +} + +#endif /* CONFIG_PPC_KUAP */ + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */ diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 3351bcf42f2d..540949b397d4 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -164,6 +164,9 @@ struct thread_struct { unsigned long rtas_sp; /* stack pointer for when in RTAS */ #endif #endif +#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP) + unsigned long kuap; /* opened segments for user access */ +#endif /* Debug Registers */ struct debug_reg debug; struct thread_fp_state fp_state; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 66202e02fee2..60b82198de7c 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -147,6 +147,9 @@ int main(void) #if defined(CONFIG_KVM) && defined(CONFIG_BOOKE) OFFSET(THREAD_KVM_VCPU, thread_struct, kvm_vcpu); #endif +#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP) + OFFSET(KUAP, thread_struct, kuap); +#endif #ifdef CONFIG_PPC_TRANSACTIONAL_MEM OFFSET(PACATMSCRATCH, paca_struct, tm_scratch); diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 69b97cc7079f..40aec3f00a05 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -387,7 +387,11 @@ DataAccess: EXCEPTION_PROLOG mfspr r10,SPRN_DSISR stw r10,_DSISR(r11) +#ifdef CONFIG_PPC_KUAP + andis. r0,r10,(DSISR_BAD_FAULT_32S | DSISR_DABRMATCH | DSISR_PROTFAULT)@h +#else andis. r0,r10,(DSISR_BAD_FAULT_32S|DSISR_DABRMATCH)@h +#endif bne 1f /* if not, try to put a PTE */ mfspr r4,SPRN_DAR /* into the hash table */ rlwinm r3,r10,32-15,21,21 /* DSISR_STORE -> _PAGE_RW */ @@ -902,6 +906,9 @@ load_up_mmu: #ifdef CONFIG_PPC_KUEP oris r3, r3, SR_NX@h /* Set Nx */ #endif +#ifdef CONFIG_PPC_KUAP + oris r3, r3, SR_KS@h /* Set Ks */ +#endif li r4,0 3: mtsrin r3,r4 addi r3,r3,0x111 /* increment VSID */ @@ -910,6 +917,7 @@ load_up_mmu: li r0, 16 - NUM_USER_SEGMENTS /* load up kernel segment registers */ mtctr r0 /* for context 0 */ rlwinm r3, r3, 0, ~SR_NX /* Nx = 0 */ + rlwinm r3, r3, 0, ~SR_KS /* Ks = 0 */ oris r3, r3, SR_KP@h /* Kp = 1 */ 3: mtsrin r3, r4 addi r3, r3, 0x111 /* increment VSID */ @@ -1020,6 +1028,9 @@ _ENTRY(switch_mmu_context) #ifdef CONFIG_PPC_KUEP oris r3, r3, SR_NX@h /* Set Nx */ #endif +#ifdef CONFIG_PPC_KUAP + oris r3, r3, SR_KS@h /* Set Ks */ +#endif li r0,NUM_USER_SEGMENTS mtctr r0 diff --git a/arch/powerpc/mm/ppc_mmu_32.c b/arch/powerpc/mm/ppc_mmu_32.c index baa75673b1f5..bf1de3ca39bc 100644 --- a/arch/powerpc/mm/ppc_mmu_32.c +++ b/arch/powerpc/mm/ppc_mmu_32.c @@ -407,3 +407,13 @@ void __init setup_kuep(bool disabled) pr_warn("KUEP cannot be disabled yet on 6xx when compiled in\n"); } #endif + +#ifdef CONFIG_PPC_KUAP +void __init setup_kuap(bool disabled) +{ + pr_info("Activating Kernel Userspace Access Protection\n"); + + if (disabled) + pr_warn("KUAP cannot be disabled yet on 6xx when compiled in\n"); +} +#endif diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 6bc0a4c08c1c..60a7c7095b05 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -26,6 +26,7 @@ config PPC_BOOK3S_32 select PPC_FPU select PPC_HAVE_PMU_SUPPORT select PPC_HAVE_KUEP + select PPC_HAVE_KUAP config PPC_85xx bool "Freescale 85xx" |