Re: [PATCH] powerpc/pseries: add new branch prediction security bits for link stack

2020-10-06 Thread Michael Ellerman 
On Tue, 25 Aug 2020 17:56:12 +1000, Nicholas Piggin wrote:
> The hypervisor interface has defined branch prediction security bits for
> handling the link stack. Wire them up.

Applied to powerpc/next.

[1/1] powerpc/pseries: add new branch prediction security bits for link stack
  https://git.kernel.org/powerpc/c/cdb1ea0276bd6a225aa1203b4829b8c3c0d4d069

cheers

[PATCH] powerpc/pseries: add new branch prediction security bits for link stack

2020-08-25 Thread Nicholas Piggin 
The hypervisor interface has defined branch prediction security bits for
handling the link stack. Wire them up.

Signed-off-by: Nicholas Piggin 
---
 arch/powerpc/include/asm/hvcall.h  | 2 ++
 arch/powerpc/platforms/pseries/setup.c | 6 ++
 2 files changed, 8 insertions(+)

diff --git a/arch/powerpc/include/asm/hvcall.h 
b/arch/powerpc/include/asm/hvcall.h
index fbb377055471..e66627fc1972 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -375,11 +375,13 @@
 #define H_CPU_CHAR_THREAD_RECONFIG_CTRL(1ull << 57) // IBM bit 6
 #define H_CPU_CHAR_COUNT_CACHE_DISABLED(1ull << 56) // IBM bit 7
 #define H_CPU_CHAR_BCCTR_FLUSH_ASSIST  (1ull << 54) // IBM bit 9
+#define H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 52) // IBM bit 11
 
 #define H_CPU_BEHAV_FAVOUR_SECURITY(1ull << 63) // IBM bit 0
 #define H_CPU_BEHAV_L1D_FLUSH_PR   (1ull << 62) // IBM bit 1
 #define H_CPU_BEHAV_BNDS_CHK_SPEC_BAR  (1ull << 61) // IBM bit 2
 #define H_CPU_BEHAV_FLUSH_COUNT_CACHE  (1ull << 58) // IBM bit 5
+#define H_CPU_BEHAV_FLUSH_LINK_STACK   (1ull << 57) // IBM bit 6
 
 /* Flag values used in H_REGISTER_PROC_TBL hcall */
 #define PROC_TABLE_OP_MASK 0x18
diff --git a/arch/powerpc/platforms/pseries/setup.c 
b/arch/powerpc/platforms/pseries/setup.c
index 2f4ee0a90284..633c45ec406d 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -519,9 +519,15 @@ static void init_cpu_char_feature_flags(struct 
h_cpu_char_result *result)
if (result->character & H_CPU_CHAR_BCCTR_FLUSH_ASSIST)
security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
 
+   if (result->character & H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST)
+   security_ftr_set(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST);
+
if (result->behaviour & H_CPU_BEHAV_FLUSH_COUNT_CACHE)
security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);
 
+   if (result->behaviour & H_CPU_BEHAV_FLUSH_LINK_STACK)
+   security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);
+
/*
 * The features below are enabled by default, so we instead look to see
 * if firmware has *disabled* them, and clear them if so.
-- 
2.23.0