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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Edward Tran <edward.tran@oracle.com>,
	Awais Tanveer <awais.tanveer@oracle.com>,
	Ankur Arora <ankur.a.arora@oracle.com>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Borislav Petkov <bp@suse.de>, Sasha Levin <sashal@kernel.org>,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org,
	peterz@infradead.org, jpoimboe@kernel.org,
	thomas.lendacky@amd.com
Subject: [PATCH AUTOSEL 5.15 35/42] x86/kexec: Disable RET on kexec
Date: Tue, 19 Jul 2022 21:13:43 -0400	[thread overview]
Message-ID: <20220720011350.1024134-35-sashal@kernel.org> (raw)
In-Reply-To: <20220720011350.1024134-1-sashal@kernel.org>

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

[ Upstream commit 697977d8415d61f3acbc4ee6d564c9dcf0309507 ]

All the invocations unroll to __x86_return_thunk and this file
must be PIC independent.

This fixes kexec on 64-bit AMD boxes.

  [ bp: Fix 32-bit build. ]

Reported-by: Edward Tran <edward.tran@oracle.com>
Reported-by: Awais Tanveer <awais.tanveer@oracle.com>
Suggested-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/relocate_kernel_32.S | 25 +++++++++++++++++++------
 arch/x86/kernel/relocate_kernel_64.S | 23 +++++++++++++++++------
 2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/relocate_kernel_32.S b/arch/x86/kernel/relocate_kernel_32.S
index fcc8a7699103..c7c4b1917336 100644
--- a/arch/x86/kernel/relocate_kernel_32.S
+++ b/arch/x86/kernel/relocate_kernel_32.S
@@ -7,10 +7,12 @@
 #include <linux/linkage.h>
 #include <asm/page_types.h>
 #include <asm/kexec.h>
+#include <asm/nospec-branch.h>
 #include <asm/processor-flags.h>
 
 /*
- * Must be relocatable PIC code callable as a C function
+ * Must be relocatable PIC code callable as a C function, in particular
+ * there must be a plain RET and not jump to return thunk.
  */
 
 #define PTR(x) (x << 2)
@@ -91,7 +93,9 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 	movl    %edi, %eax
 	addl    $(identity_mapped - relocate_kernel), %eax
 	pushl   %eax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
@@ -159,12 +163,15 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 	xorl    %edx, %edx
 	xorl    %esi, %esi
 	xorl    %ebp, %ebp
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 1:
 	popl	%edx
 	movl	CP_PA_SWAP_PAGE(%edi), %esp
 	addl	$PAGE_SIZE, %esp
 2:
+	ANNOTATE_RETPOLINE_SAFE
 	call	*%edx
 
 	/* get the re-entry point of the peer system */
@@ -190,7 +197,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 	movl	%edi, %eax
 	addl	$(virtual_mapped - relocate_kernel), %eax
 	pushl	%eax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
@@ -208,7 +217,9 @@ SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
 	popl	%edi
 	popl	%esi
 	popl	%ebx
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
@@ -271,7 +282,9 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
 	popl	%edi
 	popl	%ebx
 	popl	%ebp
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(swap_pages)
 
 	.globl kexec_control_code_size
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 5019091af059..8a9cea950e39 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -13,7 +13,8 @@
 #include <asm/unwind_hints.h>
 
 /*
- * Must be relocatable PIC code callable as a C function
+ * Must be relocatable PIC code callable as a C function, in particular
+ * there must be a plain RET and not jump to return thunk.
  */
 
 #define PTR(x) (x << 3)
@@ -104,7 +105,9 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 	/* jump to identity mapped page */
 	addq	$(identity_mapped - relocate_kernel), %r8
 	pushq	%r8
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
@@ -191,7 +194,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 	xorl	%r14d, %r14d
 	xorl	%r15d, %r15d
 
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 
 1:
 	popq	%rdx
@@ -210,7 +215,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 	call	swap_pages
 	movq	$virtual_mapped, %rax
 	pushq	%rax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
@@ -231,7 +238,9 @@ SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
 	popq	%r12
 	popq	%rbp
 	popq	%rbx
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
@@ -288,7 +297,9 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
 	lea	PAGE_SIZE(%rax), %rsi
 	jmp	0b
 3:
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(swap_pages)
 
 	.globl kexec_control_code_size
-- 
2.35.1


  parent reply	other threads:[~2022-07-20  1:21 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-20  1:13 [PATCH AUTOSEL 5.15 01/42] Revert "evm: Fix memleak in init_desc" Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 02/42] ARM: rockchip: Add missing of_node_put() in rockchip_suspend_init() Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 03/42] x86/kvm/vmx: Make noinstr clean Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 04/42] x86/cpufeatures: Move RETPOLINE flags to word 11 Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 05/42] x86/retpoline: Swizzle retpoline thunk Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 06/42] x86/vsyscall_emu/64: Don't use RET in vsyscall emulation Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 07/42] x86/sev: Avoid using __x86_return_thunk Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 08/42] objtool: Treat .text.__x86.* as noinstr Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 09/42] x86/bugs: Report AMD retbleed vulnerability Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 10/42] x86/bugs: Add AMD retbleed= boot parameter Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 11/42] x86/bugs: Enable STIBP for JMP2RET Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 12/42] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 13/42] x86/bugs: Optimize SPEC_CTRL MSR writes Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 14/42] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 15/42] x86/bugs: Report Intel retbleed vulnerability Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 16/42] x86/xen: Rename SYS* entry points Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 17/42] x86/bugs: Do IBPB fallback check only once Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 18/42] x86/cpu/amd: Add Spectral Chicken Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 19/42] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 20/42] KVM: VMX: Flatten __vmx_vcpu_run() Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 21/42] KVM: VMX: Convert launched argument to flags Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 22/42] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 23/42] wifi: mac80211: check skb_shared in ieee80211_8023_xmit() Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 24/42] wifi: mac80211: do not wake queues on a vif that is being stopped Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 25/42] wifi: cfg80211: Allow P2P client interface to indicate port authorization Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 26/42] drm: panel-orientation-quirks: Add quirk for the Lenovo Yoga Tablet 2 830 Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 27/42] nilfs2: fix incorrect masking of permission flags for symlinks Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 28/42] ASoC: ti: omap-mcbsp: duplicate sysfs error Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 29/42] ASoC: tlv320adcx140: Fix tx_mask check Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 30/42] ASoC: wm5102: Fix event generation for output compensation Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 31/42] ASoC: wm8998: Fix event generation for input mux Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 32/42] ASoC: cs47l92: Fix event generation for OUT1 demux Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 33/42] ASoC: arizona: Update arizona_aif_cfg_changed to use RX_BCLK_RATE Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 34/42] scsi: target: Fix WRITE_SAME No Data Buffer crash Sasha Levin
2022-07-20  1:13 ` Sasha Levin [this message]
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 36/42] platform/x86: asus-wmi: Add key mappings Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 37/42] platform/x86: intel_atomisp2_led: Also turn off the always-on camera LED on the Asus T100TAF Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 38/42] scsi: ufs: core: Fix missing clk change notification on host reset Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 39/42] scsi: pm80xx: Fix 'Unknown' max/min linkrate Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 40/42] scsi: pm80xx: Set stopped phy's linkrate to Disabled Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 41/42] KVM: nVMX: Always enable TSC scaling for L2 when it was enabled for L1 Sasha Levin
2022-07-20  1:13 ` [PATCH AUTOSEL 5.15 42/42] ubsan: disable UBSAN_DIV_ZERO for clang Sasha Levin

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