From: Suraj Jitindar Singh <surajjs@amazon.com>
To: <stable@vger.kernel.org>
Cc: <surajjs@amazon.com>, <sjitindarsingh@gmail.com>,
<cascardo@canonical.com>, <kvm@vger.kernel.org>,
<pbonzini@redhat.com>, <jpoimboe@kernel.org>,
<peterz@infradead.org>, <x86@kernel.org>
Subject: [PATCH 4.14 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
Date: Thu, 27 Oct 2022 13:55:12 -0700 [thread overview]
Message-ID: <20221027205512.17684-4-surajjs@amazon.com> (raw)
In-Reply-To: <20221027205512.17684-1-surajjs@amazon.com>
From: Josh Poimboeuf <jpoimboe@kernel.org>
commit b2620facef4889fefcbf2e87284f34dcd4189bce upstream.
If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants
to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be
silently disabled.
There's nothing retpoline-specific about RSB buffer filling. Remove the
CONFIG_RETPOLINE guards around it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/entry_32.S | 2 --
arch/x86/entry/entry_64.S | 2 --
arch/x86/include/asm/nospec-branch.h | 2 --
3 files changed, 6 deletions(-)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index c19974a49378..dbcea4281c30 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -245,7 +245,6 @@ ENTRY(__switch_to_asm)
movl %ebx, PER_CPU_VAR(stack_canary)+stack_canary_offset
#endif
-#ifdef CONFIG_RETPOLINE
/*
* When switching from a shallower to a deeper call stack
* the RSB may either underflow or use entries populated
@@ -254,7 +253,6 @@ ENTRY(__switch_to_asm)
* speculative execution to prevent attack.
*/
FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-#endif
/* restore callee-saved registers */
popfl
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index fee102f5a7d5..637a23d404e9 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -357,7 +357,6 @@ ENTRY(__switch_to_asm)
movq %rbx, PER_CPU_VAR(irq_stack_union)+stack_canary_offset
#endif
-#ifdef CONFIG_RETPOLINE
/*
* When switching from a shallower to a deeper call stack
* the RSB may either underflow or use entries populated
@@ -366,7 +365,6 @@ ENTRY(__switch_to_asm)
* speculative execution to prevent attack.
*/
FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-#endif
/* restore callee-saved registers */
popfq
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 0d474525caec..da81adabac94 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -145,11 +145,9 @@
* monstrosity above, manually.
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
-#ifdef CONFIG_RETPOLINE
ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
.Lskip_rsb_\@:
-#endif
.endm
#else /* __ASSEMBLY__ */
--
2.17.1
next prev parent reply other threads:[~2022-10-27 21:03 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-27 20:48 [PATCH 4.14 00/34] Retbleed & PBRSB Mitigations Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 01/34] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 02/34] x86/cpufeature: Add facility to check for min microcode revisions Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 03/34] x86/cpufeature: Fix various quality problems in the <asm/cpu_device_hd.h> header Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 04/34] x86/devicetable: Move x86 specific macro out of generic code Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 05/34] x86/cpu: Add consistent CPU match macros Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 06/34] x86/cpu: Add a steppings field to struct x86_cpu_id Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 07/34] x86/entry: Remove skip_r11rcx Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 08/34] x86/cpufeatures: Move RETPOLINE flags to word 11 Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 09/34] x86/bugs: Report AMD retbleed vulnerability Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 10/34] x86/bugs: Add AMD retbleed= boot parameter Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 11/34] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 12/34] x86/entry: Add kernel IBRS implementation Suraj Jitindar Singh
2022-10-27 20:54 ` [PATCH 4.14 13/34] x86/bugs: Optimize SPEC_CTRL MSR writes Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 14/34] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 15/34] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 16/34] x86/bugs: Report Intel retbleed vulnerability Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 17/34] entel_idle: Disable IBRS during long idle Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 18/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 19/34] x86/speculation: Add LFENCE to RSB fill sequence Suraj Jitindar Singh
2022-10-27 20:55 ` Suraj Jitindar Singh [this message]
2022-10-27 20:55 ` [PATCH 4.14 21/34] x86/speculation: Fix firmware entry SPEC_CTRL handling Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 22/34] x86/speculation: Fix SPEC_CTRL write on SMT state change Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 23/34] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 24/34] x86/speculation: Remove x86_spec_ctrl_mask Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 25/34] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 26/34] KVM: VMX: Fix IBRS handling after vmexit Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 27/34] x86/speculation: Fill RSB on vmexit for IBRS Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 28/34] x86/common: Stamp out the stepping madness Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 29/34] x86/cpu/amd: Enumerate BTC_NO Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 30/34] x86/bugs: Add Cannon lake to RETBleed affected CPU list Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 31/34] x86/speculation: Disable RRSBA behavior Suraj Jitindar Singh
2022-10-27 20:55 ` [PATCH 4.14 32/34] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Suraj Jitindar Singh
2022-10-27 20:56 ` [PATCH 4.14 33/34] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts Suraj Jitindar Singh
2022-10-27 20:56 ` [PATCH 4.14 34/34] x86/speculation: Add RSB VM Exit protections Suraj Jitindar Singh
2022-10-31 7:00 ` [PATCH 4.14 00/34] Retbleed & PBRSB Mitigations Greg KH
-- strict thread matches above, loose matches on Subject: below --
2022-10-31 7:02 [PATCH 4.14 00/34] 4.14.297-rc1 review Greg Kroah-Hartman
2022-10-31 7:02 ` [PATCH 4.14 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman
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