Changeset 0737078 in mainline

Timestamp:

2010-07-07T19:57:48Z (15 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

ed7998b

Parents:

77385fe

Message:

Rewrite the slow ia32 syscall handler to use istate_t for parameter passing and
preserving registers.

File:

• kernel/arch/ia32/src/asm.S (modified) (3 diffs)

kernel/arch/ia32/src/asm.S

@@ -245 +245 @@
         .ifeq \i - 0x30
                 /* Syscall handler */
-                pushl %ds
-                pushl %es
-                pushl %fs
-                pushl %gs
-                
+                subl $(ISTATE_SOFT_SIZE + 4), %esp
+
                 /*
                  * Push syscall arguments onto the stack
@@ -257 +254 @@
                  *       first and preserved registers next. An optimized
                  *       libc syscall wrapper can make use of this setup.
+                 *       The istate structure is arranged in the way to support
+                 *       this idea.
                  *
                  */
-                pushl %eax
-                pushl %ebp
-                pushl %edi
-                pushl %esi
-                pushl %ebx
-                pushl %ecx
-                pushl %edx
-                
-                /* We must fill the data segment registers */
-                movw $16, %ax
-                movw %ax, %ds
-                movw %ax, %es
-                
-                xorl %ebp, %ebp
+                movl %eax, ISTATE_OFFSET_EAX(%esp)
+                movl %ebx, ISTATE_OFFSET_EBX(%esp)
+                movl %ecx, ISTATE_OFFSET_ECX(%esp)
+                movl %edx, ISTATE_OFFSET_EDX(%esp)
+                movl %edi, ISTATE_OFFSET_EDI(%esp)
+                movl %esi, ISTATE_OFFSET_ESI(%esp)
+                movl %ebp, ISTATE_OFFSET_EBP(%esp)
+
+                /*
+                 * Save the selector registers.
+                 */
+                movl %gs, %ecx
+                movl %fs, %edx
+
+                movl %ecx, ISTATE_OFFSET_GS(%esp)
+                movl %edx, ISTATE_OFFSET_FS(%esp)
+
+                movl %es, %ecx
+                movl %ds, %edx
+                
+                movl %ecx, ISTATE_OFFSET_ES(%esp)
+                movl %edx, ISTATE_OFFSET_DS(%esp)
+
+                /*
+                 * Switch to kernel selectors.
+                 */
+                movl $16, %eax
+                movl %eax, %ds
+                movl %eax, %es
+                
+                movl $0, ISTATE_OFFSET_EBP_FRAME(%esp)
+                movl ISTATE_OFFSET_EIP(%esp), %eax
+                movl %eax, ISTATE_OFFSET_EIP_FRAME(%esp)
+                leal ISTATE_OFFSET_EBP_FRAME(%esp), %ebp
                 
                 cld
@@ -279 +298 @@
                 /* Call syscall_handler(edx, ecx, ebx, esi, edi, ebp, eax) */
                 call syscall_handler
-                cli
-                
-                movl 20(%esp), %ebp  /* restore EBP */
-                addl $28, %esp       /* clean-up of parameters */
-                
-                popl %gs
-                popl %fs
-                popl %es
-                popl %ds
-                
+                        
                 CLEAR_NT_FLAG
+
+                /*
+                 * Restore the selector registers.
+                 */
+                movl ISTATE_OFFSET_GS(%esp), %ecx
+                movl ISTATE_OFFSET_FS(%esp), %edx
+
+                movl %ecx, %gs
+                movl %edx, %fs
+
+                movl ISTATE_OFFSET_ES(%esp), %ecx
+                movl ISTATE_OFFSET_DS(%esp), %edx
+                        
+                movl %ecx, %es
+                movl %edx, %ds
+                        
+                /*
+                 * Restore the preserved registers the handler cloberred itself
+                 * (i.e. EBP).
+                 */
+                movl ISTATE_OFFSET_EBP(%esp), %ebp
+                        
+                addl $(ISTATE_SOFT_SIZE + 4), %esp
                 iret
+                
         .else
                 /*