All of lore.kernel.org
 help / color / mirror / Atom feed
From: Suleiman Souhlal <suleiman@google.com>
To: stable@vger.kernel.org
Cc: x86@kernel.org, kvm@vger.kernel.org, bp@alien8.de,
	pbonzini@redhat.com, peterz@infradead.org, jpoimboe@kernel.org,
	cascardo@canonical.com, surajjs@amazon.com, ssouhlal@FreeBSD.org,
	suleiman@google.com
Subject: [PATCH 4.19 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
Date: Thu, 17 Nov 2022 18:19:38 +0900	[thread overview]
Message-ID: <20221117091952.1940850-21-suleiman@google.com> (raw)
In-Reply-To: <20221117091952.1940850-1-suleiman@google.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>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
 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 37d9016d4768..78b308f2f2ea 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -643,7 +643,6 @@ 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
@@ -652,7 +651,6 @@ 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 55b61b34c462..3f418aedef8d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -367,7 +367,6 @@ 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
@@ -376,7 +375,6 @@ 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 0f4cddf621b4..ca6e421a3467 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -159,11 +159,9 @@
   * 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__ */
-- 
2.38.1.431.g37b22c650d-goog


  parent reply	other threads:[~2022-11-17  9:22 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-17  9:19 [PATCH 4.19 00/34] Intel RETBleed mitigations for 4.19 Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 01/34] Revert "x86/speculation: Add RSB VM Exit protections" Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 02/34] Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 03/34] x86/cpufeature: Add facility to check for min microcode revisions Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 04/34] x86/cpufeature: Fix various quality problems in the <asm/cpu_device_hd.h> header Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 05/34] x86/devicetable: Move x86 specific macro out of generic code Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 06/34] x86/cpu: Add consistent CPU match macros Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 07/34] x86/cpu: Add a steppings field to struct x86_cpu_id Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 08/34] x86/cpufeatures: Move RETPOLINE flags to word 11 Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 09/34] x86/bugs: Report AMD retbleed vulnerability Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 10/34] x86/bugs: Add AMD retbleed= boot parameter Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 11/34] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 12/34] x86/entry: Remove skip_r11rcx Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 13/34] x86/entry: Add kernel IBRS implementation Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 14/34] x86/bugs: Optimize SPEC_CTRL MSR writes Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 15/34] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 16/34] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 17/34] x86/bugs: Report Intel retbleed vulnerability Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 18/34] intel_idle: Disable IBRS during long idle Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 19/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Suleiman Souhlal
2022-11-17  9:19 ` Suleiman Souhlal [this message]
2022-11-17  9:19 ` [PATCH 4.19 21/34] x86/speculation: Fix firmware entry SPEC_CTRL handling Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 22/34] x86/speculation: Fix SPEC_CTRL write on SMT state change Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 23/34] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 24/34] x86/speculation: Remove x86_spec_ctrl_mask Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 25/34] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 26/34] KVM: VMX: Fix IBRS handling after vmexit Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 27/34] x86/speculation: Fill RSB on vmexit for IBRS Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 28/34] x86/common: Stamp out the stepping madness Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 29/34] x86/cpu/amd: Enumerate BTC_NO Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 30/34] x86/bugs: Add Cannon lake to RETBleed affected CPU list Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 31/34] x86/speculation: Disable RRSBA behavior Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 32/34] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 33/34] x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts Suleiman Souhlal
2022-11-17  9:19 ` [PATCH 4.19 34/34] x86/speculation: Add RSB VM Exit protections Suleiman Souhlal
2022-11-21 12:26 ` [PATCH 4.19 00/34] Intel RETBleed mitigations for 4.19 Greg KH
2022-11-21 12:43 [PATCH 4.19 00/34] 4.19.266-rc1 review Greg Kroah-Hartman
2022-11-21 12:43 ` [PATCH 4.19 20/34] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20221117091952.1940850-21-suleiman@google.com \
    --to=suleiman@google.com \
    --cc=bp@alien8.de \
    --cc=cascardo@canonical.com \
    --cc=jpoimboe@kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=ssouhlal@FreeBSD.org \
    --cc=stable@vger.kernel.org \
    --cc=surajjs@amazon.com \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.