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Subject: [RFC PATCH v1 22/28] riscv sigcontext: adding cfi state field in sigcontext
Date: Wed, 24 Jan 2024 22:21:47 -0800
Message-ID: <20240125062739.1339782-23-debug@rivosinc.com>
In-Reply-To: <20240125062739.1339782-1-debug@rivosinc.com>
References: <20240125062739.1339782-1-debug@rivosinc.com>
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From: Deepak Gupta <debug@rivosinc.com>

Shadow stack needs to be saved and restored on signal delivery and signal
return.

sigcontext embedded in ucontext is extendible. Adding cfi state in there
which can be used to save cfi state before signal delivery and restore
cfi state on sigreturn

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
---
 arch/riscv/include/uapi/asm/sigcontext.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/include/uapi/asm/sigcontext.h b/arch/riscv/include/uapi/asm/sigcontext.h
index cd4f175dc837..5ccdd94a0855 100644
--- a/arch/riscv/include/uapi/asm/sigcontext.h
+++ b/arch/riscv/include/uapi/asm/sigcontext.h
@@ -21,6 +21,10 @@ struct __sc_riscv_v_state {
 	struct __riscv_v_ext_state v_state;
 } __attribute__((aligned(16)));
 
+struct __sc_riscv_cfi_state {
+	unsigned long ss_ptr;	/* shadow stack pointer */
+	unsigned long rsvd;		/* keeping another word reserved in case we need it */
+};
 /*
  * Signal context structure
  *
@@ -29,6 +33,7 @@ struct __sc_riscv_v_state {
  */
 struct sigcontext {
 	struct user_regs_struct sc_regs;
+	struct __sc_riscv_cfi_state sc_cfi_state;
 	union {
 		union __riscv_fp_state sc_fpregs;
 		struct __riscv_extra_ext_header sc_extdesc;
-- 
2.43.0