From 2a90cf9af267c6b6c62df532398067a0f6ef659f Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 24 Nov 2021 15:03:15 +0000 Subject: [PATCH] UPSTREAM: arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations commit aff65393fa1401e034656e349abd655cfe272de0 upstream. kpti is an optional feature, for systems not using kpti a set of vectors for the spectre-bhb mitigations is needed. Add another set of vectors, __bp_harden_el1_vectors, that will be used if a mitigation is needed and kpti is not in use. The EL1 ventries are repeated verbatim as there is no additional work needed for entry from EL1. Bug: 215557547 Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman Change-Id: I0e72c5c1c366d3906bc1525e24a367989dfc98af --- arch/arm64/kernel/entry.S | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 73553e52151c..cf0d7145871f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -916,10 +916,11 @@ alternative_else_nop_endif .macro tramp_ventry, vector_start, regsize, kpti .align 7 1: - .if \kpti == 1 .if \regsize == 64 msr tpidrro_el0, x30 // Restored in kernel_ventry .endif + + .if \kpti == 1 /* * Defend against branch aliasing attacks by pushing a dummy * entry onto the return stack and using a RET instruction to @@ -1006,6 +1007,38 @@ SYM_DATA_END(__entry_tramp_data_start) #endif /* CONFIG_RANDOMIZE_BASE */ #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ +/* + * Exception vectors for spectre mitigations on entry from EL1 when + * kpti is not in use. + */ + .macro generate_el1_vector +.Lvector_start\@: + kernel_ventry 1, sync_invalid // Synchronous EL1t + kernel_ventry 1, irq_invalid // IRQ EL1t + kernel_ventry 1, fiq_invalid // FIQ EL1t + kernel_ventry 1, error_invalid // Error EL1t + + kernel_ventry 1, sync // Synchronous EL1h + kernel_ventry 1, irq // IRQ EL1h + kernel_ventry 1, fiq_invalid // FIQ EL1h + kernel_ventry 1, error // Error EL1h + + .rept 4 + tramp_ventry .Lvector_start\@, 64, kpti=0 + .endr + .rept 4 + tramp_ventry .Lvector_start\@, 32, kpti=0 + .endr + .endm + + .pushsection ".entry.text", "ax" + .align 11 +SYM_CODE_START(__bp_harden_el1_vectors) + generate_el1_vector +SYM_CODE_END(__bp_harden_el1_vectors) + .popsection + + /* * Register switch for AArch64. The callee-saved registers need to be saved * and restored. On entry: