[PATCH v7 04/14] x86/cet/ibt: Handle signals for IBT

[Yu-cheng Yu]

Setup/Restore Indirect Branch Tracking for signals.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
 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 e0ef996d3148..e1ab7e722637 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -282,6 +282,15 @@ 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_addr != 0)
+			msr_ia32_u_cet |= (current->thread.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;
@@ -322,6 +331,15 @@ 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_addr != 0)
+			msr_ia32_u_cet |= (current->thread.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