x86-32: Make sure the stack is set up before we use it
Since checkin ebba638ae7 we call
verify_cpu even in 32-bit mode. Unfortunately, calling a function
means using the stack, and the stack pointer was not initialized in
the 32-bit setup code! This code initializes the stack pointer, and
simplifies the interface slightly since it is easier to rely on just a
pointer value rather than a descriptor; we need to have different
values for the segment register anyway.
This retains start_stack as a virtual address, even though a physical
address would be more convenient for 32 bits; the 64-bit code wants
the other way around...
Reported-by: Matthieu Castet <castet.matthieu@free.fr>
LKML-Reference: <4D41E86D.8060205@free.fr>
Tested-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin
H. Peter Anvin
parent
f7448548a9
commit
11d4c3f9b6
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@ -40,10 +40,7 @@ DECLARE_EARLY_PER_CPU(u16, x86_cpu_to_apicid);
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DECLARE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid);
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/* Static state in head.S used to set up a CPU */
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extern struct {
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void *sp;
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unsigned short ss;
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} stack_start;
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extern unsigned long stack_start; /* Initial stack pointer address */
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struct smp_ops {
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void (*smp_prepare_boot_cpu)(void);
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@ -100,7 +100,7 @@ int acpi_save_state_mem(void)
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#else /* CONFIG_64BIT */
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header->trampoline_segment = setup_trampoline() >> 4;
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#ifdef CONFIG_SMP
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stack_start.sp = temp_stack + sizeof(temp_stack);
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stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
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early_gdt_descr.address =
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(unsigned long)get_cpu_gdt_table(smp_processor_id());
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initial_gs = per_cpu_offset(smp_processor_id());
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@ -85,6 +85,8 @@ RESERVE_BRK(pagetables, INIT_MAP_SIZE)
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*/
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__HEAD
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ENTRY(startup_32)
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movl pa(stack_start),%ecx
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/* test KEEP_SEGMENTS flag to see if the bootloader is asking
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us to not reload segments */
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testb $(1<<6), BP_loadflags(%esi)
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@ -99,7 +101,9 @@ ENTRY(startup_32)
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movl %eax,%es
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movl %eax,%fs
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movl %eax,%gs
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movl %eax,%ss
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2:
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leal -__PAGE_OFFSET(%ecx),%esp
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/*
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* Clear BSS first so that there are no surprises...
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@ -145,8 +149,6 @@ ENTRY(startup_32)
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* _brk_end is set up to point to the first "safe" location.
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* Mappings are created both at virtual address 0 (identity mapping)
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* and PAGE_OFFSET for up to _end.
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*
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* Note that the stack is not yet set up!
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*/
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#ifdef CONFIG_X86_PAE
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@ -282,6 +284,9 @@ ENTRY(startup_32_smp)
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movl %eax,%es
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movl %eax,%fs
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movl %eax,%gs
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movl pa(stack_start),%ecx
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movl %eax,%ss
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leal -__PAGE_OFFSET(%ecx),%esp
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#endif /* CONFIG_SMP */
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default_entry:
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@ -347,8 +352,8 @@ default_entry:
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movl %eax,%cr0 /* ..and set paging (PG) bit */
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ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */
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1:
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/* Set up the stack pointer */
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lss stack_start,%esp
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/* Shift the stack pointer to a virtual address */
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addl $__PAGE_OFFSET, %esp
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/*
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* Initialize eflags. Some BIOS's leave bits like NT set. This would
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@ -360,9 +365,7 @@ default_entry:
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#ifdef CONFIG_SMP
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cmpb $0, ready
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jz 1f /* Initial CPU cleans BSS */
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jmp checkCPUtype
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1:
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jnz checkCPUtype
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#endif /* CONFIG_SMP */
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/*
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@ -470,14 +473,7 @@ is386: movl $2,%ecx # set MP
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cld # gcc2 wants the direction flag cleared at all times
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pushl $0 # fake return address for unwinder
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#ifdef CONFIG_SMP
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movb ready, %cl
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movb $1, ready
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cmpb $0,%cl # the first CPU calls start_kernel
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je 1f
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movl (stack_start), %esp
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1:
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#endif /* CONFIG_SMP */
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jmp *(initial_code)
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/*
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@ -670,15 +666,15 @@ ENTRY(initial_page_table)
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#endif
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.data
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.balign 4
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ENTRY(stack_start)
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.long init_thread_union+THREAD_SIZE
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.long __BOOT_DS
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ready: .byte 0
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early_recursion_flag:
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.long 0
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ready: .byte 0
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int_msg:
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.asciz "Unknown interrupt or fault at: %p %p %p\n"
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@ -638,7 +638,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
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* target processor state.
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*/
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startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
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(unsigned long)stack_start.sp);
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stack_start);
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/*
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* Run STARTUP IPI loop.
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@ -785,7 +785,7 @@ do_rest:
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#endif
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early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
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initial_code = (unsigned long)start_secondary;
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stack_start.sp = (void *) c_idle.idle->thread.sp;
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stack_start = c_idle.idle->thread.sp;
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/* start_ip had better be page-aligned! */
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start_ip = setup_trampoline();
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