diff options
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 53 | ||||
| -rw-r--r-- | arch/arm64/kernel/proton-pack.c | 16 |
2 files changed, 60 insertions, 9 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 9c4ff75f983e..2ceb0c3647b4 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -646,13 +646,26 @@ alternative_else_nop_endif sub \dst, \dst, PAGE_SIZE .endm - .macro tramp_ventry, vector_start, regsize, kpti + +#define BHB_MITIGATION_NONE 0 +#define BHB_MITIGATION_LOOP 1 +#define BHB_MITIGATION_FW 2 + + .macro tramp_ventry, vector_start, regsize, kpti, bhb .align 7 1: .if \regsize == 64 msr tpidrro_el0, x30 // Restored in kernel_ventry .endif + .if \bhb == BHB_MITIGATION_LOOP + /* + * This sequence must appear before the first indirect branch. i.e. the + * ret out of tramp_ventry. It appears here because x30 is free. + */ + __mitigate_spectre_bhb_loop x30 + .endif // \bhb == BHB_MITIGATION_LOOP + .if \kpti == 1 /* * Defend against branch aliasing attacks by pushing a dummy @@ -680,6 +693,15 @@ alternative_else_nop_endif ldr x30, =vectors .endif // \kpti == 1 + .if \bhb == BHB_MITIGATION_FW + /* + * The firmware sequence must appear before the first indirect branch. + * i.e. the ret out of tramp_ventry. But it also needs the stack to be + * mapped to save/restore the registers the SMC clobbers. + */ + __mitigate_spectre_bhb_fw + .endif // \bhb == BHB_MITIGATION_FW + add x30, x30, #(1b - \vector_start + 4) ret .org 1b + 128 // Did we overflow the ventry slot? @@ -687,6 +709,9 @@ alternative_else_nop_endif .macro tramp_exit, regsize = 64 adr x30, tramp_vectors +#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY + add x30, x30, SZ_4K +#endif msr vbar_el1, x30 ldr lr, [sp, #S_LR] tramp_unmap_kernel x29 @@ -698,26 +723,32 @@ alternative_else_nop_endif sb .endm - .macro generate_tramp_vector, kpti + .macro generate_tramp_vector, kpti, bhb .Lvector_start\@: .space 0x400 .rept 4 - tramp_ventry .Lvector_start\@, 64, \kpti + tramp_ventry .Lvector_start\@, 64, \kpti, \bhb .endr .rept 4 - tramp_ventry .Lvector_start\@, 32, \kpti + tramp_ventry .Lvector_start\@, 32, \kpti, \bhb .endr .endm #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 /* * Exception vectors trampoline. + * The order must match __bp_harden_el1_vectors and the + * arm64_bp_harden_el1_vectors enum. */ .pushsection ".entry.tramp.text", "ax" .align 11 SYM_CODE_START_NOALIGN(tramp_vectors) - generate_tramp_vector kpti=1 +#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY + generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_LOOP + generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_FW +#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */ + generate_tramp_vector kpti=1, bhb=BHB_MITIGATION_NONE SYM_CODE_END(tramp_vectors) SYM_CODE_START(tramp_exit_native) @@ -744,7 +775,7 @@ SYM_DATA_END(__entry_tramp_data_start) * Exception vectors for spectre mitigations on entry from EL1 when * kpti is not in use. */ - .macro generate_el1_vector + .macro generate_el1_vector, bhb .Lvector_start\@: kernel_ventry 1, t, 64, sync // Synchronous EL1t kernel_ventry 1, t, 64, irq // IRQ EL1t @@ -757,17 +788,21 @@ SYM_DATA_END(__entry_tramp_data_start) kernel_ventry 1, h, 64, error // Error EL1h .rept 4 - tramp_ventry .Lvector_start\@, 64, kpti=0 + tramp_ventry .Lvector_start\@, 64, 0, \bhb .endr .rept 4 - tramp_ventry .Lvector_start\@, 32, kpti=0 + tramp_ventry .Lvector_start\@, 32, 0, \bhb .endr .endm +/* The order must match tramp_vecs and the arm64_bp_harden_el1_vectors enum. */ .pushsection ".entry.text", "ax" .align 11 SYM_CODE_START(__bp_harden_el1_vectors) - generate_el1_vector +#ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY + generate_el1_vector bhb=BHB_MITIGATION_LOOP + generate_el1_vector bhb=BHB_MITIGATION_FW +#endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */ SYM_CODE_END(__bp_harden_el1_vectors) .popsection diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index 9394f21d7566..6a5eeb8beea3 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -770,3 +770,19 @@ int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which) return -ENODEV; } } + +/* Patched to NOP when enabled */ +void noinstr spectre_bhb_patch_loop_mitigation_enable(struct alt_instr *alt, + __le32 *origptr, + __le32 *updptr, int nr_inst) +{ + BUG_ON(nr_inst != 1); +} + +/* Patched to NOP when enabled */ +void noinstr spectre_bhb_patch_fw_mitigation_enabled(struct alt_instr *alt, + __le32 *origptr, + __le32 *updptr, int nr_inst) +{ + BUG_ON(nr_inst != 1); +} |