irq,usermode: mask usermode flags on irq

Signed-off-by: Pawel Wieczorkiewicz <[email protected]>
KernelTestFramework · Aug 28, 2023 · c369d80 · c369d80
1 parent c5929cc
commit c369d80
Show file tree

Hide file tree

Showing 3 changed files with 14 additions and 5 deletions.
diff --git a/arch/x86/entry.S b/arch/x86/entry.S
@@ -78,10 +78,18 @@ ENTRY(entry_\sym)
 END_FUNC(entry_\sym)
 .endm
 
+.macro MASK_USER_FLAGS
+    PUSHF
+    andl $~(USERMODE_FLAGS_MASK), (%_ASM_SP)
+    POPF
+.endm
+
 .macro interrupt_handler sym func
 ENTRY(asm_interrupt_handler_\sym)
     enter_from_usermode
 
+    MASK_USER_FLAGS
+
     cld
     SAVE_ALL_REGS
     call \func

diff --git a/common/usermode.c b/common/usermode.c
@@ -83,11 +83,7 @@ static void init_syscall(void) {
     /* FIXME: Add compat support */
     wrmsr(MSR_CSTAR, _ul(NULL));
 
-    wrmsr(MSR_FMASK, X86_EFLAGS_CF | X86_EFLAGS_PF | X86_EFLAGS_AF | X86_EFLAGS_ZF |
-                         X86_EFLAGS_SF | X86_EFLAGS_TF | X86_EFLAGS_IF | X86_EFLAGS_DF |
-                         X86_EFLAGS_OF | X86_EFLAGS_ID | X86_EFLAGS_NT | X86_EFLAGS_RF |
-                         X86_EFLAGS_AC | X86_EFLAGS_IOPL);
-
+    wrmsr(MSR_FMASK, USERMODE_FLAGS_MASK);
     wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_SCE);
 }
 

diff --git a/include/usermode.h b/include/usermode.h
@@ -30,6 +30,11 @@
 #define SYSCALL_MMAP   2
 #define SYSCALL_MUNMAP 3
 
+#define USERMODE_FLAGS_MASK                                                              \
+    (X86_EFLAGS_CF | X86_EFLAGS_PF | X86_EFLAGS_AF | X86_EFLAGS_ZF | X86_EFLAGS_SF |     \
+     X86_EFLAGS_TF | X86_EFLAGS_IF | X86_EFLAGS_DF | X86_EFLAGS_OF | X86_EFLAGS_ID |     \
+     X86_EFLAGS_NT | X86_EFLAGS_RF | X86_EFLAGS_AC | X86_EFLAGS_IOPL)
+
 #ifndef __ASSEMBLY__
 #include <percpu.h>
 #include <sched.h>