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Subject[PATCH 5.4 07/43] arm64: entry.S: Add ventry overflow sanity checks
Date
From: James Morse <james.morse@arm.com>

commit 4330e2c5c04c27bebf89d34e0bc14e6943413067 upstream.

Subsequent patches add even more code to the ventry slots.
Ensure kernels that overflow a ventry slot don't get built.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kernel/entry.S | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index db137746c6fa..98991aa9d0b1 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -59,6 +59,7 @@

.macro kernel_ventry, el, label, regsize = 64
.align 7
+.Lventry_start\@:
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
alternative_if ARM64_UNMAP_KERNEL_AT_EL0
.if \el == 0
@@ -116,6 +117,7 @@ alternative_else_nop_endif
mrs x0, tpidrro_el0
#endif
b el\()\el\()_\label
+.org .Lventry_start\@ + 128 // Did we overflow the ventry slot?
.endm

.macro tramp_alias, dst, sym
@@ -1080,6 +1082,7 @@ alternative_else_nop_endif
add x30, x30, #(1b - tramp_vectors)
isb
ret
+.org 1b + 128 // Did we overflow the ventry slot?
.endm

.macro tramp_exit, regsize = 64
--
2.34.1


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