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 18/18] arm64: efi/libstub: enter with the MMU on if executing in place
Date: Wed, 30 Mar 2022 17:42:05 +0200 [thread overview]
Message-ID: <20220330154205.2483167-19-ardb@kernel.org> (raw)
In-Reply-To: <20220330154205.2483167-1-ardb@kernel.org>
If the kernel image has not been moved from the place where it was
loaded by the firmware, just call the kernel entrypoint directly, and
keep the MMU and caches enabled. This removes the need for any cache
invalidation in the entry path.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/kernel/efi-entry.S | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 61a87fa1c305..0da0b373cf32 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -23,6 +23,10 @@ SYM_CODE_START(efi_enter_kernel)
add x19, x0, x2 // relocated Image entrypoint
mov x20, x1 // DTB address
+ adrp x3, _text // just call the entrypoint
+ cmp x0, x3 // directly if the image was
+ b.eq 2f // not moved around in memory
+
/*
* Clean the copied Image to the PoC, and ensure it is not shadowed by
* stale icache entries from before relocation.
--
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 ` [RFC PATCH v2 10/18] arm64: head: record the MMU state at primary entry Ard Biesheuvel
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 ` Ard Biesheuvel [this message]
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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