[PATCH stable v4.4 0/8] missing powerpc spectre backports for 4.4

[PATCH stable v4.4 0/8] missing powerpc spectre backports for 4.4

[Diana Craciun]

Hi Greg,

These are missing patches from the initial powerpc spectre backports for 4.4.
Please queue them as well if you don't have any objections.

Thanks,

Diana Craciun (8):
  powerpc/fsl: Enable runtime patching if nospectre_v2 boot arg is used
  powerpc/fsl: Flush branch predictor when entering KVM
  powerpc/fsl: Emulate SPRN_BUCSR register
  powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)
  powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit
    platforms
  powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'
  powerpc/fsl: Add FSL_PPC_BOOK3E as supported arch for nospectre_v2
    boot arg
  Documentation: Add nospectre_v1 parameter

 Documentation/kernel-parameters.txt   |  6 +++++-
 arch/powerpc/kernel/entry_32.S        | 10 ++++++++++
 arch/powerpc/kernel/head_booke.h      | 12 ++++++++++++
 arch/powerpc/kernel/head_fsl_booke.S  | 15 +++++++++++++++
 arch/powerpc/kernel/setup_32.c        |  1 +
 arch/powerpc/kernel/setup_64.c        |  1 +
 arch/powerpc/kvm/bookehv_interrupts.S |  4 ++++
 arch/powerpc/kvm/e500_emulate.c       |  7 +++++++
 8 files changed, 55 insertions(+), 1 deletion(-)

-- 
2.17.1

[PATCH stable v4.4 1/8] powerpc/fsl: Enable runtime patching if nospectre_v2 boot arg is used

[Diana Craciun]

commit 3bc8ea8603ae4c1e09aca8de229ad38b8091fcb3 upstream.

If the user choses not to use the mitigations, replace
the code sequence with nops.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/setup_32.c | 1 +
 arch/powerpc/kernel/setup_64.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 5a9f035bcd6b..cb37f27bb928 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -323,6 +323,7 @@ void __init setup_arch(char **cmdline_p)
 	if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
 
 	setup_barrier_nospec();
+	setup_spectre_v2();
 
 	paging_init();
 
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 6bb731ababc6..11590f6cb2f9 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -737,6 +737,7 @@ void __init setup_arch(char **cmdline_p)
 		ppc_md.setup_arch();
 
 	setup_barrier_nospec();
+	setup_spectre_v2();
 
 	paging_init();
 
-- 
2.17.1

[PATCH stable v4.4 2/8] powerpc/fsl: Flush branch predictor when entering KVM

[Diana Craciun]

commit e7aa61f47b23afbec41031bc47ca8d6cb6516abc upstream.

Switching from the guest to host is another place
where the speculative accesses can be exploited.
Flush the branch predictor when entering KVM.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kvm/bookehv_interrupts.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
index 81bd8a07aa51..612b7f6a887f 100644
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S
@@ -75,6 +75,10 @@
 	PPC_LL	r1, VCPU_HOST_STACK(r4)
 	PPC_LL	r2, HOST_R2(r1)
 
+START_BTB_FLUSH_SECTION
+	BTB_FLUSH(r10)
+END_BTB_FLUSH_SECTION
+
 	mfspr	r10, SPRN_PID
 	lwz	r8, VCPU_HOST_PID(r4)
 	PPC_LL	r11, VCPU_SHARED(r4)
-- 
2.17.1

[PATCH stable v4.4 3/8] powerpc/fsl: Emulate SPRN_BUCSR register

[Diana Craciun]

commit 98518c4d8728656db349f875fcbbc7c126d4c973 upstream.

In order to flush the branch predictor the guest kernel performs
writes to the BUCSR register which is hypervisor privilleged. However,
the branch predictor is flushed at each KVM entry, so the branch
predictor has been already flushed, so just return as soon as possible
to guest.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Tweak comment formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kvm/e500_emulate.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c
index 990db69a1d0b..fa88f641ac03 100644
--- a/arch/powerpc/kvm/e500_emulate.c
+++ b/arch/powerpc/kvm/e500_emulate.c
@@ -277,6 +277,13 @@ int kvmppc_core_emulate_mtspr_e500(struct kvm_vcpu *vcpu, int sprn, ulong spr_va
 		vcpu->arch.pwrmgtcr0 = spr_val;
 		break;
 
+	case SPRN_BUCSR:
+		/*
+		 * If we are here, it means that we have already flushed the
+		 * branch predictor, so just return to guest.
+		 */
+		break;
+
 	/* extra exceptions */
 #ifdef CONFIG_SPE_POSSIBLE
 	case SPRN_IVOR32:
-- 
2.17.1

[PATCH stable v4.4 4/8] powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)

[Diana Craciun]

commit 7fef436295bf6c05effe682c8797dfcb0deb112a upstream.

In order to protect against speculation attacks on
indirect branches, the branch predictor is flushed at
kernel entry to protect for the following situations:
- userspace process attacking another userspace process
- userspace process attacking the kernel
Basically when the privillege level change (i.e.the kernel
is entered), the branch predictor state is flushed.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/head_booke.h     |  6 ++++++
 arch/powerpc/kernel/head_fsl_booke.S | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index a620203f7de3..384bb4d80520 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -42,6 +42,9 @@
 	andi.	r11, r11, MSR_PR;	/* check whether user or kernel    */\
 	mr	r11, r1;						     \
 	beq	1f;							     \
+START_BTB_FLUSH_SECTION					\
+	BTB_FLUSH(r11)						\
+END_BTB_FLUSH_SECTION					\
 	/* if from user, start at top of this thread's kernel stack */       \
 	lwz	r11, THREAD_INFO-THREAD(r10);				     \
 	ALLOC_STACK_FRAME(r11, THREAD_SIZE);				     \
@@ -127,6 +130,9 @@
 	stw	r9,_CCR(r8);		/* save CR on stack		   */\
 	mfspr	r11,exc_level_srr1;	/* check whether user or kernel    */\
 	DO_KVM	BOOKE_INTERRUPT_##intno exc_level_srr1;		             \
+START_BTB_FLUSH_SECTION								\
+	BTB_FLUSH(r10)									\
+END_BTB_FLUSH_SECTION								\
 	andi.	r11,r11,MSR_PR;						     \
 	mfspr	r11,SPRN_SPRG_THREAD;	/* if from user, start at top of   */\
 	lwz	r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index fffd1f96bb1d..275769b6fb0d 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -451,6 +451,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
 	mfcr	r13
 	stw	r13, THREAD_NORMSAVE(3)(r10)
 	DO_KVM	BOOKE_INTERRUPT_DTLB_MISS SPRN_SRR1
+START_BTB_FLUSH_SECTION
+	mfspr r11, SPRN_SRR1
+	andi. r10,r11,MSR_PR
+	beq 1f
+	BTB_FLUSH(r10)
+1:
+END_BTB_FLUSH_SECTION
 	mfspr	r10, SPRN_DEAR		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
@@ -545,6 +552,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
 	mfcr	r13
 	stw	r13, THREAD_NORMSAVE(3)(r10)
 	DO_KVM	BOOKE_INTERRUPT_ITLB_MISS SPRN_SRR1
+START_BTB_FLUSH_SECTION
+	mfspr r11, SPRN_SRR1
+	andi. r10,r11,MSR_PR
+	beq 1f
+	BTB_FLUSH(r10)
+1:
+END_BTB_FLUSH_SECTION
+
 	mfspr	r10, SPRN_SRR0		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
-- 
2.17.1

[PATCH stable v4.4 5/8] powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit platforms

[Diana Craciun]

commit c28218d4abbf4f2035495334d8bfcba64bda4787 upstream.

Used barrier_nospec to sanitize the syscall table.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/entry_32.S | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 3728e617e17e..609bc7d01f13 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -33,6 +33,7 @@
 #include <asm/unistd.h>
 #include <asm/ftrace.h>
 #include <asm/ptrace.h>
+#include <asm/barrier.h>
 
 /*
  * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE.
@@ -340,6 +341,15 @@ syscall_dotrace_cont:
 	ori	r10,r10,sys_call_table@l
 	slwi	r0,r0,2
 	bge-	66f
+
+	barrier_nospec_asm
+	/*
+	 * Prevent the load of the handler below (based on the user-passed
+	 * system call number) being speculatively executed until the test
+	 * against NR_syscalls and branch to .66f above has
+	 * committed.
+	 */
+
 	lwzx	r10,r10,r0	/* Fetch system call handler [ptr] */
 	mtlr	r10
 	addi	r9,r1,STACK_FRAME_OVERHEAD
-- 
2.17.1

[PATCH stable v4.4 6/8] powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'

[Diana Craciun]

commit 039daac5526932ec731e4499613018d263af8b3e upstream.

Fixed the following build warning:
powerpc-linux-gnu-ld: warning: orphan section `__btb_flush_fixup' from
`arch/powerpc/kernel/head_44x.o' being placed in section
`__btb_flush_fixup'.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/head_booke.h | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 384bb4d80520..7b98c7351f6c 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -31,6 +31,16 @@
  */
 #define THREAD_NORMSAVE(offset)	(THREAD_NORMSAVES + (offset * 4))
 
+#ifdef CONFIG_PPC_FSL_BOOK3E
+#define BOOKE_CLEAR_BTB(reg)									\
+START_BTB_FLUSH_SECTION								\
+	BTB_FLUSH(reg)									\
+END_BTB_FLUSH_SECTION
+#else
+#define BOOKE_CLEAR_BTB(reg)
+#endif
+
+
 #define NORMAL_EXCEPTION_PROLOG(intno)						     \
 	mtspr	SPRN_SPRG_WSCRATCH0, r10;	/* save one register */	     \
 	mfspr	r10, SPRN_SPRG_THREAD;					     \
@@ -42,9 +52,7 @@
 	andi.	r11, r11, MSR_PR;	/* check whether user or kernel    */\
 	mr	r11, r1;						     \
 	beq	1f;							     \
-START_BTB_FLUSH_SECTION					\
-	BTB_FLUSH(r11)						\
-END_BTB_FLUSH_SECTION					\
+	BOOKE_CLEAR_BTB(r11)						\
 	/* if from user, start at top of this thread's kernel stack */       \
 	lwz	r11, THREAD_INFO-THREAD(r10);				     \
 	ALLOC_STACK_FRAME(r11, THREAD_SIZE);				     \
@@ -130,9 +138,7 @@ END_BTB_FLUSH_SECTION					\
 	stw	r9,_CCR(r8);		/* save CR on stack		   */\
 	mfspr	r11,exc_level_srr1;	/* check whether user or kernel    */\
 	DO_KVM	BOOKE_INTERRUPT_##intno exc_level_srr1;		             \
-START_BTB_FLUSH_SECTION								\
-	BTB_FLUSH(r10)									\
-END_BTB_FLUSH_SECTION								\
+	BOOKE_CLEAR_BTB(r10)						\
 	andi.	r11,r11,MSR_PR;						     \
 	mfspr	r11,SPRN_SPRG_THREAD;	/* if from user, start at top of   */\
 	lwz	r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
-- 
2.17.1

[PATCH stable v4.4 7/8] powerpc/fsl: Add FSL_PPC_BOOK3E as supported arch for nospectre_v2 boot arg

[Diana Craciun]

commit f633a8ad636efb5d4bba1a047d4a0f1ef719aa06 upstream.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 Documentation/kernel-parameters.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index da515c535e62..f0bdf78420a0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2450,7 +2450,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	nohugeiomap	[KNL,x86] Disable kernel huge I/O mappings.
 
-	nospectre_v2	[X86] Disable all mitigations for the Spectre variant 2
+	nospectre_v2	[X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2
 			(indirect branch prediction) vulnerability. System may
 			allow data leaks with this option, which is equivalent
 			to spectre_v2=off.
-- 
2.17.1

Re: [PATCH stable v4.4 7/8] powerpc/fsl: Add FSL_PPC_BOOK3E as supported arch for nospectre_v2 boot arg

[Greg KH]

On Mon, Apr 29, 2019 at 06:49:07PM +0300, Diana Craciun wrote:
> commit f633a8ad636efb5d4bba1a047d4a0f1ef719aa06 upstream.

No, the patch below is not that git commit :(

I'll stop here in applying these patches.

thanks,

greg k-h

[PATCH stable v4.4 8/8] Documentation: Add nospectre_v1 parameter

[Diana Craciun]

Currently only supported on powerpc.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 Documentation/kernel-parameters.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f0bdf78420a0..3ff87d5d6fea 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2449,6 +2449,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			legacy floating-point registers on task switch.
 
 	nohugeiomap	[KNL,x86] Disable kernel huge I/O mappings.
+	
+	nospectre_v1	[PPC] Disable mitigations for Spectre Variant 1 (bounds
+			check bypass). With this option data leaks are possible
+			in the system.
 
 	nospectre_v2	[X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2
 			(indirect branch prediction) vulnerability. System may
-- 
2.17.1

Re: [PATCH stable v4.4 8/8] Documentation: Add nospectre_v1 parameter

[Greg KH]

On Mon, Apr 29, 2019 at 06:49:08PM +0300, Diana Craciun wrote:
> Currently only supported on powerpc.

No upstream git commit id for this one?

thanks,

greg k-h

Re: [PATCH stable v4.4 0/8] missing powerpc spectre backports for 4.4

[Greg KH]

On Mon, Apr 29, 2019 at 06:49:00PM +0300, Diana Craciun wrote:
> Hi Greg,
> 
> These are missing patches from the initial powerpc spectre backports for 4.4.
> Please queue them as well if you don't have any objections.

I applied the first 6 of these now.  If you could fix up the last two
and resend them, that would be wonderful.

thanks,

greg k-h