mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-10-01 01:35:54 -04:00
95 lines
3.0 KiB
Diff
95 lines
3.0 KiB
Diff
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diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
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index db230f8..1a454d0 100644
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--- a/arch/x86/kernel/entry_64.S
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+++ b/arch/x86/kernel/entry_64.S
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@@ -1068,6 +1068,7 @@
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jnz native_irq_return_ldt
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#endif
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+.global native_irq_return_iret
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native_irq_return_iret:
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iretq
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_ASM_EXTABLE(native_irq_return_iret, bad_iret)
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@@ -1164,37 +1165,6 @@
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CFI_ENDPROC
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END(common_interrupt)
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- /*
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- * If IRET takes a fault on the espfix stack, then we
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- * end up promoting it to a doublefault. In that case,
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- * modify the stack to make it look like we just entered
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- * the #GP handler from user space, similar to bad_iret.
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- */
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-#ifdef CONFIG_X86_ESPFIX64
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- ALIGN
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-__do_double_fault:
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- XCPT_FRAME 1 RDI+8
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- movq RSP(%rdi),%rax /* Trap on the espfix stack? */
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- sarq $PGDIR_SHIFT,%rax
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- cmpl $ESPFIX_PGD_ENTRY,%eax
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- jne do_double_fault /* No, just deliver the fault */
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- cmpl $__KERNEL_CS,CS(%rdi)
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- jne do_double_fault
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- movq RIP(%rdi),%rax
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- cmpq $native_irq_return_iret,%rax
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- jne do_double_fault /* This shouldn't happen... */
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- movq PER_CPU_VAR(kernel_stack),%rax
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- subq $(6*8-KERNEL_STACK_OFFSET),%rax /* Reset to original stack */
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- movq %rax,RSP(%rdi)
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- movq $0,(%rax) /* Missing (lost) #GP error code */
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- movq $general_protection,RIP(%rdi)
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- retq
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- CFI_ENDPROC
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-END(__do_double_fault)
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-#else
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-# define __do_double_fault do_double_fault
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-#endif
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-
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/*
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* End of kprobes section
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*/
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@@ -1363,7 +1333,7 @@
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zeroentry bounds do_bounds
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zeroentry invalid_op do_invalid_op
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zeroentry device_not_available do_device_not_available
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-paranoiderrorentry double_fault __do_double_fault
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+paranoiderrorentry double_fault do_double_fault
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zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
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errorentry invalid_TSS do_invalid_TSS
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errorentry segment_not_present do_segment_not_present
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diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
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index 772e2a8..74e0801 100644
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--- a/arch/x86/kernel/traps.c
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+++ b/arch/x86/kernel/traps.c
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@@ -247,6 +247,30 @@
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static const char str[] = "double fault";
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struct task_struct *tsk = current;
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+#ifdef CONFIG_X86_ESPFIX64
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+ extern unsigned char native_irq_return_iret[];
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+
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+ /*
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+ * If IRET takes a non-IST fault on the espfix64 stack, then we
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+ * end up promoting it to a doublefault. In that case, modify
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+ * the stack to make it look like we just entered the #GP
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+ * handler from user space, similar to bad_iret.
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+ */
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+ if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY &&
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+ regs->cs == __KERNEL_CS &&
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+ regs->ip == (unsigned long)native_irq_return_iret)
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+ {
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+ struct pt_regs *normal_regs = task_pt_regs(current);
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+
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+ /* Fake a #GP(0) from userspace. */
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+ memmove(&normal_regs->ip, (void *)regs->sp, 5*8);
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+ normal_regs->orig_ax = 0; /* Missing (lost) #GP error code */
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+ regs->ip = (unsigned long)general_protection;
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+ regs->sp = (unsigned long)&normal_regs->orig_ax;
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+ return;
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+ }
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+#endif
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+
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exception_enter();
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/* Return not checked because double check cannot be ignored */
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notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
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