From: "Rémi Denis-Courmont" <remi@remlab.net>
To: catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] arm64: reduce trampoline data alignment
Date: Mon, 16 Mar 2020 14:40:46 +0200 [thread overview]
Message-ID: <20200316124046.103844-3-remi@remlab.net> (raw)
From: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
The trampoline data, currently consisting of two relocated pointers,
must be within a single page. However, there are no needs for it to
start a page.
This reduces the alignment to 16 bytes (with SDEI) or 8 bytes (without
SDEI), which is sufficient to ensure that the data is entirely within a
single page of the fixmap.
Signed-off-by: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
---
arch/arm64/kernel/entry.S | 4 ++--
arch/arm64/mm/mmu.c | 5 ++---
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index af17fcb4aaea..b648f9fe1e33 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -858,12 +858,12 @@ SYM_CODE_END(tramp_exit_compat)
.popsection // .entry.tramp.text
#ifdef CONFIG_RANDOMIZE_BASE
.pushsection ".rodata", "a"
- .align PAGE_SHIFT
#ifdef CONFIG_ARM_SDE_INTERFACE
+ .align 4 // all .rodata must be in a single fixmap page
SYM_DATA_START(__sdei_asm_trampoline_next_handler)
.quad __sdei_asm_handler
SYM_DATA_END(__sdei_asm_trampoline_next_handler)
-#endif
+#endif /* CONFIG_ARM_SDE_INTERFACE */
SYM_DATA_START(__entry_tramp_data_start)
.quad vectors
SYM_DATA_END(__entry_tramp_data_start)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9b08f7c7e6f0..6a0e75f48e7b 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -599,9 +599,8 @@ static int __init map_entry_trampoline(void)
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
extern char __entry_tramp_data_start[];
- __set_fixmap(FIX_ENTRY_TRAMP_DATA,
- __pa_symbol(__entry_tramp_data_start),
- PAGE_KERNEL_RO);
+ pa_start = __pa_symbol(__entry_tramp_data_start) & PAGE_MASK;
+ __set_fixmap(FIX_ENTRY_TRAMP_DATA, pa_start, PAGE_KERNEL_RO);
}
return 0;
--
2.25.1
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next reply other threads:[~2020-03-16 12:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-16 12:40 Rémi Denis-Courmont [this message]
2020-03-17 22:34 ` [PATCH 3/3] arm64: reduce trampoline data alignment Will Deacon
-- strict thread matches above, loose matches on Subject: below --
2020-03-19 9:12 [PATCHv3 0/3] clean up KPTI / SDEI " Rémi Denis-Courmont
2020-03-19 9:14 ` [PATCH 3/3] arm64: reduce " Rémi Denis-Courmont
2020-03-21 13:40 ` Catalin Marinas
2020-03-23 11:58 ` Mark Rutland
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