321 lines
7.1 KiB
ArmAsm
321 lines
7.1 KiB
ArmAsm
/*
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*
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* Copyright 2013 Google Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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.align 4
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.global exception_stack_end
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exception_stack_end:
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.long 0
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.global exception_state
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exception_state:
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.long 0
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/* Some temporary variables which are used while saving exception state. */
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vector:
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.long 0
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error_code:
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.long 0
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old_esp:
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.long 0
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old_eax:
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.long 0
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.align 8
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/*
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* Each exception vector has a small stub associated with it which sets aside
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* the error code, if any, records which vector we entered from, and calls
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* the common exception entry point. Some exceptions have error codes and some
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* don't, so we have a macro for each type.
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*/
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.macro stub num
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exception_stub_\num:
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movl $0, error_code
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movl $\num, vector
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jmp exception_common
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.endm
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.macro stub_err num
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exception_stub_\num:
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popl error_code
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movl $\num, vector
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jmp exception_common
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.endm
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.altmacro
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.macro user_defined_stubs from, to
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stub \from
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.if \to-\from
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user_defined_stubs %(from+1),\to
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.endif
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.endm
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stub 0
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stub 1
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stub 2
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stub 3
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stub 4
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stub 5
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stub 6
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stub 7
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stub_err 8
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stub 9
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stub_err 10
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stub_err 11
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stub_err 12
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stub_err 13
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stub_err 14
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stub 15
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stub 16
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stub_err 17
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stub 18
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stub 19
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stub 20
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stub 21
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stub 22
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stub 23
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stub 24
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stub 25
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stub 26
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stub 27
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stub 28
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stub 29
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stub_err 30
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stub 31
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/* Split the macro so we avoid a stack overflow. */
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user_defined_stubs 32, 63
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user_defined_stubs 64, 127
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user_defined_stubs 128, 191
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user_defined_stubs 192, 255
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exception_common:
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/*
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* Save off the stack pointer and old eax value and install the
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* exception stack. eax points to the old stack which has the
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* exception ip, cs, and flags.
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*/
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mov %esp, old_esp
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addl $12, old_esp
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mov %eax, old_eax
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mov %esp, %eax
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mov exception_stack_end, %esp
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/*
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* Push values onto the top of the exception stack to form an
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* exception state structure.
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*/
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pushl vector
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pushl error_code
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pushl %gs
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pushl %fs
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pushl %es
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pushl %ds
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pushl %ss
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pushl 4(%eax)
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pushl 8(%eax)
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pushl (%eax)
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pushl %edi
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pushl %esi
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pushl %ebp
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pushl old_esp
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pushl %ebx
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pushl %edx
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pushl %ecx
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pushl old_eax
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/*
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* Call the C exception handler. It will find the exception state
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* using the exception_state global pointer. Not
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* passing parameters means we don't have to worry about what ABI
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* is being used.
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*/
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mov %esp, exception_state
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call exception_dispatch
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/*
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* Restore state from the exception state structure, including any
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* changes that might have been made.
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*/
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popl old_eax
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popl %ecx
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popl %edx
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popl %ebx
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popl old_esp
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mov old_esp, %eax
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subl $12, %eax
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popl %ebp
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popl %esi
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popl %edi
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popl (%eax)
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popl 8(%eax)
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popl 4(%eax)
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popl %ss
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popl %ds
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popl %es
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popl %fs
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popl %gs
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mov %eax, %esp
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mov old_eax, %eax
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/* Return from the exception. */
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iretl
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/*
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* We need segment selectors for the IDT, so we need to know where things are
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* in the GDT. We set one up here which is pretty standard and largely copied
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* from coreboot.
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*/
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.align 8
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gdt:
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/* selgdt 0, unused */
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.word 0x0000, 0x0000
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.byte 0x00, 0x00, 0x00, 0x00
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/* selgdt 8, unused */
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.word 0x0000, 0x0000
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.byte 0x00, 0x00, 0x00, 0x00
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/* selgdt 0x10, flat 4GB code segment */
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.word 0xffff, 0x0000
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.byte 0x00, 0x9b, 0xcf, 0x00
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/* selgdt 0x18, flat 4GB data segment */
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.word 0xffff, 0x0000
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.byte 0x00, 0x93, 0xcf, 0x00
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gdt_end:
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/* GDT pointer for use with lgdt */
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gdt_ptr:
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.word gdt_end - gdt - 1
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.long gdt
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/*
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* Record the target and construct the actual entry at init time. This
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* is necessary because the linker doesn't want to construct the entry
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* for us.
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*/
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.macro interrupt_gate target
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.long \target
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.long \target
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.endm
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.altmacro
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.macro user_defined_gates from, to
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interrupt_gate exception_stub_\from
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.if \to-\from
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user_defined_gates %(from+1),\to
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.endif
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.endm
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.align 8
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.global idt
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idt:
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interrupt_gate exception_stub_0
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interrupt_gate exception_stub_1
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interrupt_gate exception_stub_2
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interrupt_gate exception_stub_3
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interrupt_gate exception_stub_4
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interrupt_gate exception_stub_5
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interrupt_gate exception_stub_6
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interrupt_gate exception_stub_7
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interrupt_gate exception_stub_8
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interrupt_gate exception_stub_9
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interrupt_gate exception_stub_10
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interrupt_gate exception_stub_11
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interrupt_gate exception_stub_12
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interrupt_gate exception_stub_13
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interrupt_gate exception_stub_14
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interrupt_gate exception_stub_15
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interrupt_gate exception_stub_16
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interrupt_gate exception_stub_17
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interrupt_gate exception_stub_18
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interrupt_gate exception_stub_19
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interrupt_gate exception_stub_20
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interrupt_gate exception_stub_21
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interrupt_gate exception_stub_22
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interrupt_gate exception_stub_23
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interrupt_gate exception_stub_24
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interrupt_gate exception_stub_25
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interrupt_gate exception_stub_26
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interrupt_gate exception_stub_27
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interrupt_gate exception_stub_28
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interrupt_gate exception_stub_29
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interrupt_gate exception_stub_30
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interrupt_gate exception_stub_31
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user_defined_gates 32, 63
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user_defined_gates 64, 127
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user_defined_gates 128, 191
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user_defined_gates 192, 255
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idt_end:
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/* IDT pointer for use with lidt */
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idt_ptr:
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.word idt_end - idt - 1
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.long idt
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.global exception_init_asm
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exception_init_asm:
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/* Save eax so we can use it as a temporary variable. */
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pushl %eax
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/* Install the GDT. */
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lgdt gdt_ptr
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/* Load the segment registers from it. */
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ljmp $0x10, $1f
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1: movl $0x18, %eax
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movl %eax, %ds
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movl %eax, %es
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movl %eax, %ss
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movl %eax, %fs
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movl %eax, %gs
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/*
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* Loop over the entries which start out as two copies of the target
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* address. We can turn them into real interrupt gates by selectively
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* replacing certain bit fields.
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*/
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movl $idt, %eax
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1:
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andl $0x0000ffff, (%eax)
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orl $0x00100000, (%eax)
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andl $0xffff0000, 4(%eax)
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orl $0x0000ee00, 4(%eax)
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addl $8, %eax
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cmp $idt_end, %eax
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jne 1b
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/* Install the IDT. */
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lidt idt_ptr
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/* Restore eax and return to the caller. */
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popl %eax
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ret
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