Changes in kernel/arch/amd64/src/asm.S [f77e591d:c0e9f3f] 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
 
-.macro handler i
-.global int_\i
-int_\i:
-
+#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
+        
         /*
          * Choose between version with error code and version without error
-         * code.
+         * 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.
          */
         
@@ -278 +290 @@
         addq $(ISTATE_SOFT_SIZE + 8), %rsp
         iretq
+        
+        .align INTERRUPT_ALIGN
+        .if (\n - \i) - 1
+                handler "(\i + 1)", \n
+        .endif
 .endm
 
-#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
-
+.align INTERRUPT_ALIGN
 interrupt_handlers:
-.irp cnt, LIST_0_63
-        handler \cnt 
-.endr
+        h_start:
+                handler 0 IDT_ITEMS
+        h_end:
 
 /** Low-level syscall handler
@@ -321 +334 @@
         movq %gs:8, %rsp  /* set this thread's kernel RSP */
         
-        /*
-         * 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 */
+        /* Switch back to remain consistent */
         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
-
-        /*
-         * Call syscall_handler() with the 7th argument passed on stack.
-         */
+        pushq %rax
+        
         call syscall_handler
         
+        addq $8, %rsp
+        
+        popq %rbp
+        popq %r11
+        popq %rcx
+        
         cli
-        
-        /*
-         * 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
-
+        swapgs
+        
+        /* Restore the user RSP */
+        movq %gs:0, %rsp
+        swapgs
+        
         sysretq
 
@@ -532 +509 @@
         ret
 
+.data
+.global interrupt_handler_size
+
+interrupt_handler_size: .quad (h_end - h_start) / IDT_ITEMS