Changes in kernel/arch/amd64/src/asm.S [c0e9f3f:f77e591d] in mainline

File:

• kernel/arch/amd64/src/asm.S (modified) (4 diffs)

kernel/arch/amd64/src/asm.S

@@ -192 +192 @@
 #define ERROR_WORD_INTERRUPT_LIST  0x00027D00
 
-#define INTERRUPT_ALIGN         256 
-
-/** Declare interrupt handlers
- *
- * Declare interrupt handlers for n interrupt
- * vectors starting at vector i.
- *
- * The handlers call exc_dispatch().
- *
- */
-.macro handler i n
-        
+.macro handler i
+.global int_\i
+int_\i:
+
         /*
          * Choose between version with error code and version without error
-         * code. Both versions have to be of the same size. amd64 assembly is,
-         * however, a little bit tricky. For instance, subq $0x80, %rsp and
-         * subq $0x78, %rsp can result in two instructions with different
-         * op-code lengths.
-         * Therefore we align the interrupt handlers.
+         * code.
          */
         
@@ -290 +278 @@
         addq $(ISTATE_SOFT_SIZE + 8), %rsp
         iretq
-        
-        .align INTERRUPT_ALIGN
-        .if (\n - \i) - 1
-                handler "(\i + 1)", \n
-        .endif
 .endm
 
-.align INTERRUPT_ALIGN
+#define LIST_0_63 \
+        0, 1, 2, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,\
+        28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,\
+        53,54,55,56,57,58,59,60,61,62,63
+
 interrupt_handlers:
-        h_start:
-                handler 0 IDT_ITEMS
-        h_end:
+.irp cnt, LIST_0_63
+        handler \cnt 
+.endr
 
 /** Low-level syscall handler
@@ -334 +321 @@
         movq %gs:8, %rsp  /* set this thread's kernel RSP */
         
-        /* Switch back to remain consistent */
+        /*
+         * Note that the space needed for the imitated istate structure has been
+         * preallocated for us in thread_create_arch() and set in
+         * before_thread_runs_arch().
+         */
+
+        /*
+         * Save the general purpose registers and push the 7th argument (syscall
+         * number) onto the stack. Note that the istate structure has a layout
+         * which supports this.
+         */
+        movq %rax, ISTATE_OFFSET_RAX(%rsp)  /* 7th argument, passed on stack */
+        movq %rbx, ISTATE_OFFSET_RBX(%rsp)  /* observability */
+        movq %rcx, ISTATE_OFFSET_RCX(%rsp)  /* userspace RIP */
+        movq %rdx, ISTATE_OFFSET_RDX(%rsp)  /* 3rd argument, observability */
+        movq %rsi, ISTATE_OFFSET_RSI(%rsp)  /* 2nd argument, observability */ 
+        movq %rdi, ISTATE_OFFSET_RDI(%rsp)  /* 1st argument, observability */
+        movq %rbp, ISTATE_OFFSET_RBP(%rsp)  /* need to preserve userspace RBP */
+        movq %r8, ISTATE_OFFSET_R8(%rsp)    /* 5th argument, observability */
+        movq %r9, ISTATE_OFFSET_R9(%rsp)    /* 6th argument, observability */
+        movq %r10, ISTATE_OFFSET_R10(%rsp)  /* 4th argument, observability */
+        movq %r11, ISTATE_OFFSET_R11(%rsp)  /* low 32 bits userspace RFLAGS */
+        movq %r12, ISTATE_OFFSET_R12(%rsp)  /* observability */
+        movq %r13, ISTATE_OFFSET_R13(%rsp)  /* observability */
+        movq %r14, ISTATE_OFFSET_R14(%rsp)  /* observability */
+        movq %r15, ISTATE_OFFSET_R15(%rsp)  /* observability */
+
+        /*
+         * Save the return address and the userspace stack on locations that
+         * would normally be taken by them.
+         */
+        movq %gs:0, %rax
+        movq %rax, ISTATE_OFFSET_RSP(%rsp)
+        movq %rcx, ISTATE_OFFSET_RIP(%rsp)
+
+        /*
+         * Imitate a regular stack frame linkage.
+         */
+        movq $0, ISTATE_OFFSET_RBP_FRAME(%rsp)
+        movq %rcx, ISTATE_OFFSET_RIP_FRAME(%rsp)
+        leaq ISTATE_OFFSET_RBP_FRAME(%rsp), %rbp
+
+        /* Switch back to normal %gs */
         swapgs
         sti
         
-        pushq %rcx
-        pushq %r11
-        pushq %rbp
-        
-        xorq %rbp, %rbp  /* stop the stack traces here */
-        
         /* Copy the 4th argument where it is expected  */
         movq %r10, %rcx
-        pushq %rax
-        
+
+        /*
+         * Call syscall_handler() with the 7th argument passed on stack.
+         */
         call syscall_handler
         
-        addq $8, %rsp
-        
-        popq %rbp
-        popq %r11
-        popq %rcx
-        
         cli
-        swapgs
-        
-        /* Restore the user RSP */
-        movq %gs:0, %rsp
-        swapgs
-        
+        
+        /*
+         * Restore registers needed for return via the SYSRET instruction and
+         * the clobbered preserved registers (i.e. RBP).
+         */
+        movq ISTATE_OFFSET_RBP(%rsp), %rbp
+        movq ISTATE_OFFSET_RCX(%rsp), %rcx
+        movq ISTATE_OFFSET_R11(%rsp), %r11
+        movq ISTATE_OFFSET_RSP(%rsp), %rsp
+
         sysretq
 
@@ -509 +532 @@
         ret
 
-.data
-.global interrupt_handler_size
-
-interrupt_handler_size: .quad (h_end - h_start) / IDT_ITEMS