From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>
Subject: [PATCH 4.14 11/27] arm64: entry: Free up another register on kptis tramp_exit path
Date: Fri, 1 Apr 2022 08:36:21 +0200 [thread overview]
Message-ID: <20220401063624.553108289@linuxfoundation.org> (raw)
In-Reply-To: <20220401063624.232282121@linuxfoundation.org>
From: James Morse <james.morse@arm.com>
commit 03aff3a77a58b5b52a77e00537a42090ad57b80b upstream.
Kpti stashes x30 in far_el1 while it uses x30 for all its work.
Making the vectors a per-cpu data structure will require a second
register.
Allow tramp_exit two registers before it unmaps the kernel, by
leaving x30 on the stack, and stashing x29 in far_el1.
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/kernel/entry.S | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -356,14 +356,16 @@ alternative_else_nop_endif
ldp x24, x25, [sp, #16 * 12]
ldp x26, x27, [sp, #16 * 13]
ldp x28, x29, [sp, #16 * 14]
- ldr lr, [sp, #S_LR]
- add sp, sp, #S_FRAME_SIZE // restore sp
.if \el == 0
-alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
+alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
+ ldr lr, [sp, #S_LR]
+ add sp, sp, #S_FRAME_SIZE // restore sp
+ eret
+alternative_else_nop_endif
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
bne 4f
- msr far_el1, x30
+ msr far_el1, x29
tramp_alias x30, tramp_exit_native
br x30
4:
@@ -371,6 +373,8 @@ alternative_insn eret, nop, ARM64_UNMAP_
br x30
#endif
.else
+ ldr lr, [sp, #S_LR]
+ add sp, sp, #S_FRAME_SIZE // restore sp
eret
.endif
.endm
@@ -1048,10 +1052,12 @@ alternative_insn isb, nop, ARM64_WORKARO
.macro tramp_exit, regsize = 64
adr x30, tramp_vectors
msr vbar_el1, x30
- tramp_unmap_kernel x30
+ ldr lr, [sp, #S_LR]
+ tramp_unmap_kernel x29
.if \regsize == 64
- mrs x30, far_el1
+ mrs x29, far_el1
.endif
+ add sp, sp, #S_FRAME_SIZE // restore sp
eret
.endm
next prev parent reply other threads:[~2022-04-01 6:39 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 6:36 [PATCH 4.14 00/27] 4.14.275-rc1 review Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 01/27] arm64: arch_timer: Add workaround for ARM erratum 1188873 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 02/27] arm64: arch_timer: avoid unused function warning Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 03/27] arm64: Add silicon-errata.txt entry for ARM erratum 1188873 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 04/27] arm64: Make ARM64_ERRATUM_1188873 depend on COMPAT Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 05/27] arm64: Add part number for Neoverse N1 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 06/27] arm64: Add part number for Arm Cortex-A77 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 07/27] arm64: Add Neoverse-N2, Cortex-A710 CPU part definition Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 08/27] arm64: Add Cortex-X2 " Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 09/27] arm64: entry.S: Add ventry overflow sanity checks Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 10/27] arm64: entry: Make the trampoline cleanup optional Greg Kroah-Hartman
2022-04-01 6:36 ` Greg Kroah-Hartman [this message]
2022-04-01 6:36 ` [PATCH 4.14 12/27] arm64: entry: Move the trampoline data page before the text page Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 13/27] arm64: entry: Allow tramp_alias to access symbols after the 4K boundary Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 14/27] arm64: entry: Dont assume tramp_vectors is the start of the vectors Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 15/27] arm64: entry: Move trampoline macros out of ifdefd section Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 16/27] arm64: entry: Make the kpti trampolines kpti sequence optional Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 17/27] arm64: entry: Allow the trampoline text to occupy multiple pages Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 18/27] arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 19/27] arm64: entry: Add vectors that have the bhb mitigation sequences Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 20/27] arm64: entry: Add macro for reading symbol addresses from the trampoline Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 21/27] arm64: Add percpu vectors for EL1 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 22/27] arm64: proton-pack: Report Spectre-BHB vulnerabilities as part of Spectre-v2 Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 23/27] KVM: arm64: Add templates for BHB mitigation sequences Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 24/27] arm64: Mitigate spectre style branch history side channels Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 25/27] KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 26/27] arm64: add ID_AA64ISAR2_EL1 sys register Greg Kroah-Hartman
2022-04-01 6:36 ` [PATCH 4.14 27/27] arm64: Use the clearbhb instruction in mitigations Greg Kroah-Hartman
2022-04-01 10:43 ` [PATCH 4.14 00/27] 4.14.275-rc1 review Guenter Roeck
2022-04-01 18:26 ` Naresh Kamboju
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