diff mbox series

[v9,18/36] x86/fred: Add a page fault entry stub for FRED

Message ID 20230731063317.3720-19-xin3.li@intel.com
State New
Headers
Series x86: enable FRED for x86-64 |

Commit Message

Li, Xin3 July 31, 2023, 6:32 a.m. UTC 
  From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Add a page fault entry stub for FRED.

On a FRED system, the faulting address (CR2) is passed on the stack,
to avoid the problem of transient state. Thus we get the page fault
address from the stack instead of CR2.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
 arch/x86/include/asm/fred.h |  2 ++
 arch/x86/mm/fault.c         | 18 ++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
index b45c1bea5b7f..fb8e7b4f2d38 100644
--- a/arch/x86/include/asm/fred.h
+++ b/arch/x86/include/asm/fred.h
@@ -112,6 +112,8 @@  static __always_inline unsigned long fred_event_data(struct pt_regs *regs)
 
 typedef DECLARE_FRED_HANDLER((*fred_handler));
 
+DECLARE_FRED_HANDLER(fred_exc_page_fault);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* CONFIG_X86_FRED */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e8711b2cafaf..dd3df092d0f2 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -34,6 +34,7 @@ 
 #include <asm/kvm_para.h>		/* kvm_handle_async_pf		*/
 #include <asm/vdso.h>			/* fixup_vdso_exception()	*/
 #include <asm/irq_stack.h>
+#include <asm/fred.h>
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -1495,9 +1496,10 @@  handle_page_fault(struct pt_regs *regs, unsigned long error_code,
 	}
 }
 
-DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault)
+static __always_inline void page_fault_common(struct pt_regs *regs,
+					      unsigned int error_code,
+					      unsigned long address)
 {
-	unsigned long address = read_cr2();
 	irqentry_state_t state;
 
 	prefetchw(&current->mm->mmap_lock);
@@ -1544,3 +1546,15 @@  DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault)
 
 	irqentry_exit(regs, state);
 }
+
+DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault)
+{
+	page_fault_common(regs, error_code, read_cr2());
+}
+
+#ifdef CONFIG_X86_FRED
+DEFINE_FRED_HANDLER(fred_exc_page_fault)
+{
+	page_fault_common(regs, regs->orig_ax, fred_event_data(regs));
+}
+#endif