To allow efi_enter_kernel() to be shared with the EFI zboot decompressor build, drop another reference to dcache_clean_poc() and replace it with a single DC CVAC instruction. To ensure that it covers the remainder of efi_enter_kernel() as intended, reorganize the code a bit so it fits in a 32-byte cacheline, and align it to 32 bytes. (Even though the architecture defines 16 as the minimum D-cache line size, even the chosen value of 32 is highly unlikely to ever be encountered on real hardware, and this works with any line size >= 32) Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/arm64/kernel/efi-entry.S | 57 ++++++++++---------- 1 file changed, 29 insertions(+), 28 deletions(-) diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S index 1c1be004a271..8bce13356e29 100644 --- a/arch/arm64/kernel/efi-entry.S +++ b/arch/arm64/kernel/efi-entry.S @@ -21,40 +21,41 @@ SYM_CODE_START(efi_enter_kernel) */ ldr w2, =primary_entry_offset add x19, x0, x2 // relocated Image entrypoint - mov x20, x1 // DTB address + + mov x0, x1 // DTB address + mov x1, xzr + mov x2, xzr + mov x3, xzr /* * Clean the remainder of this routine to the PoC * so that we can safely disable the MMU and caches. */ - adr x0, 0f - adr x1, 3f - bl dcache_clean_poc -0: + adr x4, 1f + dc civac, x4 + dsb sy + /* Turn off Dcache and MMU */ - mrs x0, CurrentEL - cmp x0, #CurrentEL_EL2 - b.ne 1f - mrs x0, sctlr_el2 - bic x0, x0, #1 << 0 // clear SCTLR.M - bic x0, x0, #1 << 2 // clear SCTLR.C - pre_disable_mmu_workaround - msr sctlr_el2, x0 - isb + mrs x4, CurrentEL + cmp x4, #CurrentEL_EL2 + mrs x4, sctlr_el1 + b.ne 0f + mrs x4, sctlr_el2 +0: bic x4, x4, #SCTLR_ELx_M + bic x4, x4, #SCTLR_ELx_C + b.eq 1f b 2f -1: - mrs x0, sctlr_el1 - bic x0, x0, #1 << 0 // clear SCTLR.M - bic x0, x0, #1 << 2 // clear SCTLR.C - pre_disable_mmu_workaround - msr sctlr_el1, x0 + + .balign 32 +1: pre_disable_mmu_workaround + msr sctlr_el2, x4 isb -2: - /* Jump to kernel entry point */ - mov x0, x20 - mov x1, xzr - mov x2, xzr - mov x3, xzr - br x19 -3: + br x19 // jump to kernel entrypoint + +2: pre_disable_mmu_workaround + msr sctlr_el1, x4 + isb + br x19 // jump to kernel entrypoint + + .org 1b + 32 SYM_CODE_END(efi_enter_kernel) -- 2.35.1
