[PATCH v8 03/14] x86/cet/ibt: Handle signals for end branch

Yu-cheng Yu
2019-08-13T21:04:57Z

Restore end branch tracking setting from thread header.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/kernel/cet.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 505a69f476e1..db542bd423cc 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -281,6 +281,15 @@ int cet_restore_signal(bool ia32, struct sc_ext *sc_ext)
msr_ia32_u_cet |= MSR_IA32_CET_SHSTK_EN;
}

+ if (current->thread.cet.ibt_enabled) {
+ if (current->thread.cet.ibt_bitmap_used)
+ msr_ia32_u_cet |= (IBT_BITMAP_ADDR |
+ MSR_IA32_CET_LEG_IW_EN);
+
+ msr_ia32_u_cet |= (MSR_IA32_CET_ENDBR_EN |
+ MSR_IA32_CET_NO_TRACK_EN);
+ }
+
wrmsrl(MSR_IA32_PL3_SSP, new_ssp);
wrmsrl(MSR_IA32_U_CET, msr_ia32_u_cet);
return 0;
@@ -321,6 +330,15 @@ int cet_setup_signal(bool ia32, unsigned long rstor_addr, struct sc_ext *sc_ext)
sc_ext->ssp = new_ssp;
}

+ if (current->thread.cet.ibt_enabled) {
+ if (current->thread.cet.ibt_bitmap_used)
+ msr_ia32_u_cet |= (IBT_BITMAP_ADDR |
+ MSR_IA32_CET_LEG_IW_EN);
+
+ msr_ia32_u_cet |= (MSR_IA32_CET_ENDBR_EN |
+ MSR_IA32_CET_NO_TRACK_EN);
+ }
+
modify_fpu_regs_begin();
wrmsrl(MSR_IA32_PL3_SSP, ssp);
wrmsrl(MSR_IA32_U_CET, msr_ia32_u_cet);
--
2.17.1