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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 5.16 26/37] arm64: entry: Make the kpti trampolines kpti sequence optional
Date: Wed,  9 Mar 2022 17:00:27 +0100	[thread overview]
Message-ID: <20220309155859.847045161@linuxfoundation.org> (raw)
In-Reply-To: <20220309155859.086952723@linuxfoundation.org>

From: James Morse <james.morse@arm.com>

commit c47e4d04ba0f1ea17353d85d45f611277507e07a upstream.

Spectre-BHB needs to add sequences to the vectors. Having one global
set of vectors is a problem for big/little systems where the sequence
is costly on cpus that are not vulnerable.

Making the vectors per-cpu in the style of KVM's bh_harden_hyp_vecs
requires the vectors to be generated by macros.

Make the kpti re-mapping of the kernel optional, so the macros can be
used without kpti.

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
@@ -646,9 +646,10 @@ alternative_else_nop_endif
 	sub	\dst, \dst, PAGE_SIZE
 	.endm
 
-	.macro tramp_ventry, vector_start, regsize
+	.macro tramp_ventry, vector_start, regsize, kpti
 	.align	7
 1:
+	.if	\kpti == 1
 	.if	\regsize == 64
 	msr	tpidrro_el0, x30	// Restored in kernel_ventry
 	.endif
@@ -671,9 +672,14 @@ alternative_insn isb, nop, ARM64_WORKARO
 alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM
 	prfm	plil1strm, [x30, #(1b - \vector_start)]
 alternative_else_nop_endif
+
 	msr	vbar_el1, x30
-	add	x30, x30, #(1b - \vector_start + 4)
 	isb
+	.else
+	ldr	x30, =vectors
+	.endif // \kpti == 1
+
+	add	x30, x30, #(1b - \vector_start + 4)
 	ret
 .org 1b + 128	// Did we overflow the ventry slot?
 	.endm
@@ -691,15 +697,15 @@ alternative_else_nop_endif
 	sb
 	.endm
 
-	.macro	generate_tramp_vector
+	.macro	generate_tramp_vector,	kpti
 .Lvector_start\@:
 	.space	0x400
 
 	.rept	4
-	tramp_ventry	.Lvector_start\@, 64
+	tramp_ventry	.Lvector_start\@, 64, \kpti
 	.endr
 	.rept	4
-	tramp_ventry	.Lvector_start\@, 32
+	tramp_ventry	.Lvector_start\@, 32, \kpti
 	.endr
 	.endm
 
@@ -710,7 +716,7 @@ alternative_else_nop_endif
 	.pushsection ".entry.tramp.text", "ax"
 	.align	11
 SYM_CODE_START_NOALIGN(tramp_vectors)
-	generate_tramp_vector
+	generate_tramp_vector	kpti=1
 SYM_CODE_END(tramp_vectors)
 
 SYM_CODE_START(tramp_exit_native)



  parent reply	other threads:[~2022-03-09 16:12 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-09 16:00 [PATCH 5.16 00/37] 5.16.14-rc1 review Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 01/37] x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 02/37] x86/speculation: Add eIBRS + Retpoline options Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 03/37] Documentation/hw-vuln: Update spectre doc Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 04/37] x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 05/37] x86/speculation: Use generic retpoline by default on AMD Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 06/37] x86/speculation: Update link to AMD speculation whitepaper Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 07/37] x86/speculation: Warn about Spectre v2 LFENCE mitigation Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 08/37] x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 09/37] ARM: report Spectre v2 status through sysfs Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 10/37] ARM: early traps initialisation Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 11/37] ARM: use LOADADDR() to get load address of sections Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 12/37] ARM: Spectre-BHB workaround Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 13/37] ARM: include unprivileged BPF status in Spectre V2 reporting Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 14/37] arm64: add ID_AA64ISAR2_EL1 sys register Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 15/37] arm64: cpufeature: add HWCAP for FEAT_AFP Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 16/37] arm64: cpufeature: add HWCAP for FEAT_RPRES Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 17/37] arm64: entry.S: Add ventry overflow sanity checks Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 18/37] arm64: spectre: Rename spectre_v4_patch_fw_mitigation_conduit Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 19/37] KVM: arm64: Allow indirect vectors to be used without SPECTRE_V3A Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 20/37] arm64: entry: Make the trampoline cleanup optional Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 21/37] arm64: entry: Free up another register on kptis tramp_exit path Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 22/37] arm64: entry: Move the trampoline data page before the text page Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 23/37] arm64: entry: Allow tramp_alias to access symbols after the 4K boundary Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 24/37] arm64: entry: Dont assume tramp_vectors is the start of the vectors Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 25/37] arm64: entry: Move trampoline macros out of ifdefd section Greg Kroah-Hartman
2022-03-09 16:00 ` Greg Kroah-Hartman [this message]
2022-03-09 16:00 ` [PATCH 5.16 27/37] arm64: entry: Allow the trampoline text to occupy multiple pages Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 28/37] arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 29/37] arm64: entry: Add vectors that have the bhb mitigation sequences Greg Kroah-Hartman
2022-03-10 23:27   ` Pavel Machek
2022-03-11  8:15     ` Greg Kroah-Hartman
2022-03-11  8:39       ` Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 30/37] arm64: entry: Add macro for reading symbol addresses from the trampoline Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 31/37] arm64: Add percpu vectors for EL1 Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 32/37] arm64: proton-pack: Report Spectre-BHB vulnerabilities as part of Spectre-v2 Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 33/37] arm64: Mitigate spectre style branch history side channels Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 34/37] KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 35/37] arm64: Use the clearbhb instruction in mitigations Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 36/37] arm64: proton-pack: Include unprivileged eBPF status in Spectre v2 mitigation reporting Greg Kroah-Hartman
2022-03-09 16:00 ` [PATCH 5.16 37/37] ARM: fix build error when BPF_SYSCALL is disabled Greg Kroah-Hartman
2022-03-09 19:05 ` [PATCH 5.16 00/37] 5.16.14-rc1 review Guenter Roeck
2022-03-09 20:01   ` Greg Kroah-Hartman
2022-03-09 21:17     ` Greg Kroah-Hartman
2022-03-09 20:23 ` Shuah Khan
2022-03-09 21:17 ` Daniel Díaz
2022-03-09 21:19   ` Daniel Díaz
2022-03-09 21:49 ` Fox Chen
2022-03-10 10:50 ` Bagas Sanjaya

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