From: Alexandre Chartre <alexandre.chartre@oracle.com>
To: "tglx@linutronix.de"@aserv0122.oracle.com,
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Subject: [RFC][PATCH 08/24] x86/entry: Add C version of SWAPGS and SWAPGS_UNSAFE_STACK
Date: Mon, 9 Nov 2020 12:23:03 +0100 [thread overview]
Message-ID: <20201109112319.264511-9-alexandre.chartre@oracle.com> (raw)
In-Reply-To: <20201109112319.264511-1-alexandre.chartre@oracle.com>
SWAPGS and SWAPGS_UNSAFE_STACK are assembly macros. Add C versions
of these macros (swapgs() and swapgs_unsafe_stack()).
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
arch/x86/include/asm/paravirt.h | 15 +++++++++++++++
arch/x86/include/asm/paravirt_types.h | 17 ++++++++++++-----
2 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index d25cc6830e89..a4898130b36b 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -145,6 +145,21 @@ static inline void __write_cr4(unsigned long x)
PVOP_VCALL1(cpu.write_cr4, x);
}
+static inline void swapgs(void)
+{
+ PVOP_VCALL0(cpu.swapgs);
+}
+
+/*
+ * If swapgs is used while the userspace stack is still current,
+ * there's no way to call a pvop. The PV replacement *must* be
+ * inlined, or the swapgs instruction must be trapped and emulated.
+ */
+static inline void swapgs_unsafe_stack(void)
+{
+ PVOP_VCALL0_ALT(cpu.swapgs, "swapgs");
+}
+
static inline void arch_safe_halt(void)
{
PVOP_VCALL0(irq.safe_halt);
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0fad9f61c76a..eea9acc942a3 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -532,12 +532,12 @@ int paravirt_disable_iospace(void);
pre, post, ##__VA_ARGS__)
-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, pre, post, ...) \
+#define ____PVOP_VCALL(op, insn, clbr, call_clbr, extra_clbr, pre, post, ...) \
({ \
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
+ paravirt_alt(insn) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -547,12 +547,17 @@ int paravirt_disable_iospace(void);
})
#define __PVOP_VCALL(op, pre, post, ...) \
- ____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
- VEXTRA_CLOBBERS, \
+ ____PVOP_VCALL(op, PARAVIRT_CALL, CLBR_ANY, \
+ PVOP_VCALL_CLOBBERS, VEXTRA_CLOBBERS, \
pre, post, ##__VA_ARGS__)
+#define __PVOP_VCALL_ALT(op, insn) \
+ ____PVOP_VCALL(op, insn, CLBR_ANY, \
+ PVOP_VCALL_CLOBBERS, VEXTRA_CLOBBERS, \
+ "", "")
+
#define __PVOP_VCALLEESAVE(op, pre, post, ...) \
- ____PVOP_VCALL(op.func, CLBR_RET_REG, \
+ ____PVOP_VCALL(op.func, PARAVIRT_CALL, CLBR_RET_REG, \
PVOP_VCALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)
@@ -562,6 +567,8 @@ int paravirt_disable_iospace(void);
__PVOP_CALL(rettype, op, "", "")
#define PVOP_VCALL0(op) \
__PVOP_VCALL(op, "", "")
+#define PVOP_VCALL0_ALT(op, insn) \
+ __PVOP_VCALL_ALT(op, insn)
#define PVOP_CALLEE0(rettype, op) \
__PVOP_CALLEESAVE(rettype, op, "", "")
--
2.18.4
next prev parent reply other threads:[~2020-11-09 11:22 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 11:22 [RFC][PATCH 00/24] x86/pti: Defer CR3 switch to C code Alexandre Chartre
2020-11-09 11:22 ` [RFC][PATCH 01/24] x86/syscall: Add wrapper for invoking syscall function Alexandre Chartre
2020-11-09 17:25 ` Andy Lutomirski
2020-11-09 17:45 ` Alexandre Chartre
2020-11-09 11:22 ` [RFC][PATCH 02/24] x86/entry: Update asm_call_on_stack to support more function arguments Alexandre Chartre
2020-11-09 11:22 ` [RFC][PATCH 03/24] x86/entry: Consolidate IST entry from userspace Alexandre Chartre
2020-11-09 11:22 ` [RFC][PATCH 04/24] x86/sev-es: Define a setup stack function for the VC idtentry Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 05/24] x86/entry: Implement ret_from_fork body with C code Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 06/24] x86/pti: Provide C variants of PTI switch CR3 macros Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 07/24] x86/entry: Fill ESPFIX stack using C code Alexandre Chartre
2020-11-09 11:23 ` Alexandre Chartre [this message]
2020-11-09 17:38 ` [RFC][PATCH 08/24] x86/entry: Add C version of SWAPGS and SWAPGS_UNSAFE_STACK Andy Lutomirski
2020-11-09 18:04 ` Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 09/24] x86/entry: Add C version of paranoid_entry/exit Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 10/24] x86/pti: Introduce per-task PTI trampoline stack Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 11/24] x86/pti: Function to clone page-table entries from a specified mm Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 12/24] x86/pti: Function to map per-cpu page-table entry Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 13/24] x86/pti: Extend PTI user mappings Alexandre Chartre
2020-11-09 17:28 ` Andy Lutomirski
2020-11-09 17:52 ` Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 14/24] x86/pti: Use PTI stack instead of trampoline stack Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 15/24] x86/pti: Execute syscall functions on the kernel stack Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 16/24] x86/pti: Execute IDT handlers " Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 17/24] x86/pti: Execute IDT handlers with error code " Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 18/24] x86/pti: Execute system vector handlers " Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 19/24] x86/pti: Execute page fault handler " Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 20/24] x86/pti: Execute NMI " Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 21/24] x86/entry: Disable stack-protector for IST entry C handlers Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 22/24] x86/entry: Defer paranoid entry/exit to C code Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 23/24] x86/entry: Remove paranoid_entry and paranoid_exit Alexandre Chartre
2020-11-09 11:23 ` [RFC][PATCH 24/24] x86/pti: Defer CR3 switch to C code for non-IST and syscall entries Alexandre Chartre
2020-11-09 14:00 ` [RFC][PATCH 00/24] x86/pti: Defer CR3 switch to C code Alexandre Chartre
2020-11-09 14:44 Alexandre Chartre
2020-11-09 14:44 ` [RFC][PATCH 08/24] x86/entry: Add C version of SWAPGS and SWAPGS_UNSAFE_STACK Alexandre Chartre
2020-11-09 19:55 ` Alexandre Chartre
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