From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org, keescook@chromium.org,
mark.rutland@arm.com, catalin.marinas@arm.com,
Ard Biesheuvel <ardb@kernel.org>
Subject: [RFC PATCH v2 10/18] arm64: head: record the MMU state at primary entry
Date: Wed, 30 Mar 2022 17:41:57 +0200 [thread overview]
Message-ID: <20220330154205.2483167-11-ardb@kernel.org> (raw)
In-Reply-To: <20220330154205.2483167-1-ardb@kernel.org>
Prepare for being able to deal with primary entry with the MMU and
caches enabled, by recording whether or not we entered with the MMU on
in register x22.
While at it, add disable_mmu_workaround macro invocations to
init_kernel_el, as its manipulation of SCTLR_ELx may come down to
disabling of the MMU after subsequent patches.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/kernel/head.S | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index f3b096daf1c5..44e2e39046a9 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -83,9 +83,11 @@
*
* Register Scope Purpose
* x21 primary_entry() .. start_kernel() FDT pointer passed at boot in x0
+ * x22 primary_entry() .. start_kernel() whether we entered with the MMU on
* x23 __primary_switch() .. relocate_kernel() physical misalignment/KASLR offset
*/
SYM_CODE_START(primary_entry)
+ bl record_mmu_state
bl preserve_boot_args
bl init_kernel_el // w0=cpu_boot_mode
bl set_cpu_boot_mode_flag
@@ -101,6 +103,17 @@ SYM_CODE_START(primary_entry)
b __primary_switch
SYM_CODE_END(primary_entry)
+SYM_CODE_START_LOCAL(record_mmu_state)
+ mrs x22, CurrentEL
+ cmp x22, #CurrentEL_EL2
+ mrs x22, sctlr_el1
+ b.ne 0f
+ mrs x22, sctlr_el2
+0: tst x22, #SCTLR_ELx_M
+ cset w22, ne
+ ret
+SYM_CODE_END(record_mmu_state)
+
/*
* Preserve the arguments passed by the bootloader in x0 .. x3
*/
@@ -485,6 +498,7 @@ SYM_FUNC_START(init_kernel_el)
SYM_INNER_LABEL(init_el1, SYM_L_LOCAL)
mov_q x0, INIT_SCTLR_EL1_MMU_OFF
+ pre_disable_mmu_workaround
msr sctlr_el1, x0
isb
mov_q x0, INIT_PSTATE_EL1
@@ -516,6 +530,7 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
/* Switching to VHE requires a sane SCTLR_EL1 as a start */
mov_q x0, INIT_SCTLR_EL1_MMU_OFF
+ pre_disable_mmu_workaround
msr_s SYS_SCTLR_EL12, x0
/*
@@ -531,6 +546,7 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
1:
mov_q x0, INIT_SCTLR_EL1_MMU_OFF
+ pre_disable_mmu_workaround
msr sctlr_el1, x0
msr elr_el2, lr
--
2.30.2
next prev parent reply other threads:[~2022-03-30 15:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-30 15:41 [RFC PATCH v2 00/18] arm64: efi: leave MMU and caches on at boot Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 01/18] arm64: head: drop idmap_ptrs_per_pgd Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 02/18] arm64: head: split off idmap creation code Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 03/18] arm64: kernel: drop unnecessary PoC cache clean+invalidate Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 04/18] arm64: head: cover entire kernel image in ID map Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 05/18] arm64: head: factor out TTBR1 assignment into a macro Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 06/18] arm64: head: populate kernel page tables with MMU and caches on Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 07/18] arm64: kaslr: deal with init called with VA randomization enabled Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 08/18] arm64: setup: defer R/O remapping of FDT Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 09/18] arm64: head: relocate kernel only a single time if KASLR is enabled Ard Biesheuvel
2022-03-30 15:41 ` Ard Biesheuvel [this message]
2022-03-30 15:41 ` [RFC PATCH v2 11/18] arm64: mm: make vabits_actual a build time constant if possible Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 12/18] arm64: head: avoid cache invalidation when entering with the MMU on Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 13/18] arm64: head: record CPU boot mode after enabling the MMU Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 14/18] arm64: head: clean the ID map page to the PoC Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 15/18] arm64: lds: move idmap_pg_dir out of .rodata Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 16/18] efi: libstub: pass image handle to handle_kernel_image() Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 17/18] efi/arm64: libstub: run image in place if randomized by the loader Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 18/18] arm64: efi/libstub: enter with the MMU on if executing in place Ard Biesheuvel
2022-03-31 15:37 ` [RFC PATCH v2 00/18] arm64: efi: leave MMU and caches on at boot Mark Rutland
2022-03-31 16:20 ` Ard Biesheuvel
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