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-rw-r--r--arch/i386/kernel/asm-offsets.c5
-rw-r--r--arch/i386/kernel/cpu/common.c11
-rw-r--r--arch/i386/kernel/entry.S73
-rw-r--r--arch/i386/kernel/head.S2
-rw-r--r--arch/i386/kernel/traps.c57
5 files changed, 55 insertions, 93 deletions
diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c
index c80271f8f08..e94d910a28b 100644
--- a/arch/i386/kernel/asm-offsets.c
+++ b/arch/i386/kernel/asm-offsets.c
@@ -58,6 +58,11 @@ void foo(void)
OFFSET(TI_sysenter_return, thread_info, sysenter_return);
BLANK();
+ OFFSET(GDS_size, Xgt_desc_struct, size);
+ OFFSET(GDS_address, Xgt_desc_struct, address);
+ OFFSET(GDS_pad, Xgt_desc_struct, pad);
+ BLANK();
+
OFFSET(EXEC_DOMAIN_handler, exec_domain, handler);
OFFSET(RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext);
BLANK();
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index d9f3e3c31f0..5532fc4e1bf 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -24,9 +24,6 @@
DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr);
-DEFINE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
-EXPORT_PER_CPU_SYMBOL(cpu_16bit_stack);
-
static int cachesize_override __cpuinitdata = -1;
static int disable_x86_fxsr __cpuinitdata;
static int disable_x86_serial_nr __cpuinitdata = 1;
@@ -603,7 +600,6 @@ void __cpuinit cpu_init(void)
struct tss_struct * t = &per_cpu(init_tss, cpu);
struct thread_struct *thread = &current->thread;
struct desc_struct *gdt;
- __u32 stk16_off = (__u32)&per_cpu(cpu_16bit_stack, cpu);
struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
if (cpu_test_and_set(cpu, cpu_initialized)) {
@@ -651,13 +647,6 @@ old_gdt:
* and set up the GDT descriptor:
*/
memcpy(gdt, cpu_gdt_table, GDT_SIZE);
-
- /* Set up GDT entry for 16bit stack */
- *(__u64 *)(&gdt[GDT_ENTRY_ESPFIX_SS]) |=
- ((((__u64)stk16_off) << 16) & 0x000000ffffff0000ULL) |
- ((((__u64)stk16_off) << 32) & 0xff00000000000000ULL) |
- (CPU_16BIT_STACK_SIZE - 1);
-
cpu_gdt_descr->size = GDT_SIZE - 1;
cpu_gdt_descr->address = (unsigned long)gdt;
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 5a63d6fdb70..c38d801ba0b 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -48,6 +48,7 @@
#include <asm/smp.h>
#include <asm/page.h>
#include <asm/desc.h>
+#include <asm/percpu.h>
#include <asm/dwarf2.h>
#include "irq_vectors.h"
@@ -418,23 +419,18 @@ ldt_ss:
* This is an "official" bug of all the x86-compatible
* CPUs, which we can try to work around to make
* dosemu and wine happy. */
- subl $8, %esp # reserve space for switch16 pointer
- CFI_ADJUST_CFA_OFFSET 8
+ movl OLDESP(%esp), %eax
+ movl %esp, %edx
+ call patch_espfix_desc
+ pushl $__ESPFIX_SS
+ CFI_ADJUST_CFA_OFFSET 4
+ pushl %eax
+ CFI_ADJUST_CFA_OFFSET 4
DISABLE_INTERRUPTS
TRACE_IRQS_OFF
- movl %esp, %eax
- /* Set up the 16bit stack frame with switch32 pointer on top,
- * and a switch16 pointer on top of the current frame. */
- call setup_x86_bogus_stack
- CFI_ADJUST_CFA_OFFSET -8 # frame has moved
- TRACE_IRQS_IRET
- RESTORE_REGS
- lss 20+4(%esp), %esp # switch to 16bit stack
-1: INTERRUPT_RETURN
-.section __ex_table,"a"
- .align 4
- .long 1b,iret_exc
-.previous
+ lss (%esp), %esp
+ CFI_ADJUST_CFA_OFFSET -8
+ jmp restore_nocheck
CFI_ENDPROC
# perform work that needs to be done immediately before resumption
@@ -524,30 +520,30 @@ syscall_badsys:
CFI_ENDPROC
#define FIXUP_ESPFIX_STACK \
- movl %esp, %eax; \
- /* switch to 32bit stack using the pointer on top of 16bit stack */ \
- lss %ss:CPU_16BIT_STACK_SIZE-8, %esp; \
- /* copy data from 16bit stack to 32bit stack */ \
- call fixup_x86_bogus_stack; \
- /* put ESP to the proper location */ \
- movl %eax, %esp;
-#define UNWIND_ESPFIX_STACK \
+ /* since we are on a wrong stack, we cant make it a C code :( */ \
+ GET_THREAD_INFO(%ebp); \
+ movl TI_cpu(%ebp), %ebx; \
+ PER_CPU(cpu_gdt_descr, %ebx); \
+ movl GDS_address(%ebx), %ebx; \
+ GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
+ addl %esp, %eax; \
+ pushl $__KERNEL_DS; \
+ CFI_ADJUST_CFA_OFFSET 4; \
pushl %eax; \
CFI_ADJUST_CFA_OFFSET 4; \
+ lss (%esp), %esp; \
+ CFI_ADJUST_CFA_OFFSET -8;
+#define UNWIND_ESPFIX_STACK \
movl %ss, %eax; \
- /* see if on 16bit stack */ \
+ /* see if on espfix stack */ \
cmpw $__ESPFIX_SS, %ax; \
- je 28f; \
-27: popl %eax; \
- CFI_ADJUST_CFA_OFFSET -4; \
-.section .fixup,"ax"; \
-28: movl $__KERNEL_DS, %eax; \
+ jne 27f; \
+ movl $__KERNEL_DS, %eax; \
movl %eax, %ds; \
movl %eax, %es; \
- /* switch to 32bit stack */ \
+ /* switch to normal stack */ \
FIXUP_ESPFIX_STACK; \
- jmp 27b; \
-.previous
+27:;
/*
* Build the entry stubs and pointer table with
@@ -614,7 +610,6 @@ error_code:
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET eax, 0
- xorl %eax, %eax
pushl %ebp
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ebp, 0
@@ -627,7 +622,6 @@ error_code:
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx, 0
- decl %eax # eax = -1
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx, 0
@@ -644,7 +638,7 @@ error_code:
/*CFI_REGISTER es, ecx*/
movl ES(%esp), %edi # get the function address
movl ORIG_EAX(%esp), %edx # get the error code
- movl %eax, ORIG_EAX(%esp)
+ movl $-1, ORIG_EAX(%esp)
movl %ecx, ES(%esp)
/*CFI_REL_OFFSET es, ES*/
movl $(__USER_DS), %ecx
@@ -754,7 +748,7 @@ KPROBE_ENTRY(nmi)
cmpw $__ESPFIX_SS, %ax
popl %eax
CFI_ADJUST_CFA_OFFSET -4
- je nmi_16bit_stack
+ je nmi_espfix_stack
cmpl $sysenter_entry,(%esp)
je nmi_stack_fixup
pushl %eax
@@ -797,7 +791,7 @@ nmi_debug_stack_check:
FIX_STACK(24,nmi_stack_correct, 1)
jmp nmi_stack_correct
-nmi_16bit_stack:
+nmi_espfix_stack:
/* We have a RING0_INT_FRAME here.
*
* create the pointer to lss back
@@ -806,7 +800,6 @@ nmi_16bit_stack:
CFI_ADJUST_CFA_OFFSET 4
pushl %esp
CFI_ADJUST_CFA_OFFSET 4
- movzwl %sp, %esp
addw $4, (%esp)
/* copy the iret frame of 12 bytes */
.rept 3
@@ -817,11 +810,11 @@ nmi_16bit_stack:
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
FIXUP_ESPFIX_STACK # %eax == %esp
- CFI_ADJUST_CFA_OFFSET -20 # the frame has now moved
xorl %edx,%edx # zero error code
call do_nmi
RESTORE_REGS
- lss 12+4(%esp), %esp # back to 16bit stack
+ lss 12+4(%esp), %esp # back to espfix stack
+ CFI_ADJUST_CFA_OFFSET -24
1: INTERRUPT_RETURN
CFI_ENDPROC
.section __ex_table,"a"
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index ca31f18d277..b1f1df11fcc 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -584,7 +584,7 @@ ENTRY(cpu_gdt_table)
.quad 0x00009a000000ffff /* 0xc0 APM CS 16 code (16 bit) */
.quad 0x004092000000ffff /* 0xc8 APM DS data */
- .quad 0x0000920000000000 /* 0xd0 - ESPFIX 16-bit SS */
+ .quad 0x00c0920000000000 /* 0xd0 - ESPFIX SS */
.quad 0x0000000000000000 /* 0xd8 - unused */
.quad 0x0000000000000000 /* 0xe0 - unused */
.quad 0x0000000000000000 /* 0xe8 - unused */
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 56655ea8d98..f9bb1f89d68 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -1088,49 +1088,24 @@ fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
#endif
}
-fastcall void setup_x86_bogus_stack(unsigned char * stk)
+fastcall unsigned long patch_espfix_desc(unsigned long uesp,
+ unsigned long kesp)
{
- unsigned long *switch16_ptr, *switch32_ptr;
- struct pt_regs *regs;
- unsigned long stack_top, stack_bot;
- unsigned short iret_frame16_off;
int cpu = smp_processor_id();
- /* reserve the space on 32bit stack for the magic switch16 pointer */
- memmove(stk, stk + 8, sizeof(struct pt_regs));
- switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs));
- regs = (struct pt_regs *)stk;
- /* now the switch32 on 16bit stack */
- stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
- stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
- switch32_ptr = (unsigned long *)(stack_top - 8);
- iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20;
- /* copy iret frame on 16bit stack */
- memcpy((void *)(stack_bot + iret_frame16_off), &regs->eip, 20);
- /* fill in the switch pointers */
- switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off;
- switch16_ptr[1] = __ESPFIX_SS;
- switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) +
- 8 - CPU_16BIT_STACK_SIZE;
- switch32_ptr[1] = __KERNEL_DS;
-}
-
-fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp)
-{
- unsigned long *switch32_ptr;
- unsigned char *stack16, *stack32;
- unsigned long stack_top, stack_bot;
- int len;
- int cpu = smp_processor_id();
- stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
- stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
- switch32_ptr = (unsigned long *)(stack_top - 8);
- /* copy the data from 16bit stack to 32bit stack */
- len = CPU_16BIT_STACK_SIZE - 8 - sp;
- stack16 = (unsigned char *)(stack_bot + sp);
- stack32 = (unsigned char *)
- (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len);
- memcpy(stack32, stack16, len);
- return stack32;
+ struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
+ struct desc_struct *gdt = (struct desc_struct *)cpu_gdt_descr->address;
+ unsigned long base = (kesp - uesp) & -THREAD_SIZE;
+ unsigned long new_kesp = kesp - base;
+ unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
+ __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
+ /* Set up base for espfix segment */
+ desc &= 0x00f0ff0000000000ULL;
+ desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
+ ((((__u64)base) << 32) & 0xff00000000000000ULL) |
+ ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
+ (lim_pages & 0xffff);
+ *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
+ return new_kesp;
}
/*
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 06:32:34 +0000