exception: Make space in the stack for full exception context

This is step 1 of the rework to make reentrant exceptions work

Signed-off-by: Hector Martin <marcan@marcan.st>

proxyclient/m1n1/proxy.py

@@ -67,14 +67,14 @@ class EXC_RET(IntEnum):
     STEP = 4
 
 ExcInfo = Struct(
-    "cpu_id" / Int64ul,
+    "regs" / Array(32, Int64ul),
     "spsr" / RegAdapter(SPSR),
     "elr" / Int64ul,
     "esr" / RegAdapter(ESR),
     "far" / Int64ul,
     "afsr1" / Int64ul,
-    "regs" / Array(31, Int64ul),
     "sp" / Array(3, Int64ul),
+    "cpu_id" / Int64ul,
     "mpidr" / Int64ul,
     "elr_phys" / Int64ul,
     "far_phys" / Int64ul,

src/exception.h

@@ -3,6 +3,11 @@
 #ifndef __EXCEPTION_H__
 #define __EXCEPTION_H__
 
+#define SIZEOF_EXC_INFO (64 * 8)
+
+#ifndef __ASSEMBLER__
+
+#include <assert.h>
 #include <stdint.h>
 
 #include "types.h"
@@ -16,6 +21,24 @@ enum exc_guard_t {
     GUARD_SILENT = 0x100,
 };
 
+struct exc_info {
+    u64 regs[32];
+    u64 spsr;
+    u64 elr;
+    u64 esr;
+    u64 far;
+    u64 afsr1;
+    u64 sp[3];
+    u64 cpu_id;
+    u64 mpidr;
+    u64 elr_phys;
+    u64 far_phys;
+    u64 sp_phys;
+    void *extra;
+};
+static_assert(sizeof(struct exc_info) <= SIZEOF_EXC_INFO, "Please increase SIZEOF_EXC_INFO");
+static_assert((sizeof(struct exc_info) & 15) == 0, "SIZEOF_EXC_INFO must be a multiple of 16");
+
 extern volatile enum exc_guard_t exc_guard;
 extern volatile int exc_count;
 
@@ -28,3 +51,5 @@ uint64_t el0_call(void *func, uint64_t a, uint64_t b, uint64_t c, uint64_t d);
 uint64_t el1_call(void *func, uint64_t a, uint64_t b, uint64_t c, uint64_t d);
 
 #endif
+
+#endif

src/exception_asm.S

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: MIT */
 
+#include "exception.h"
 #include "memory.h"
 
 .globl exc_sync
@@ -13,6 +14,7 @@
 .type _v_sp0_sync, @function
 _v_sp0_sync:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _exc_entry
     bl exc_sync
@@ -23,6 +25,7 @@ _v_sp0_sync:
 .type _v_sp0_irq, @function
 _v_sp0_irq:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _exc_entry
     bl exc_irq
@@ -33,6 +36,7 @@ _v_sp0_irq:
 .type _v_sp0_fiq, @function
 _v_sp0_fiq:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _exc_entry
     bl exc_fiq
@@ -43,6 +47,7 @@ _v_sp0_fiq:
 .type _v_sp0_serr, @function
 _v_sp0_serr:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _exc_entry
     bl exc_serr
@@ -84,10 +89,11 @@ _exc_return:
     ldp x14, x15, [sp], #16
     ldp x16, x17, [sp], #16
     ldr x18, [sp], #8
-
     add sp, sp, #88
-
     ldr x30, [sp], #16
+
+    add sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
+
     eret
 
 .globl el0_call

src/gxf_asm.S

@@ -1,7 +1,8 @@
 /* SPDX-License-Identifier: MIT */
 
-#include "cpu_regs.h"
 #include "gxf.h"
+#include "cpu_regs.h"
+#include "exception.h"
 
 #define genter .long 0x00201420
 #define gexit .long 0x00201400
@@ -161,6 +162,7 @@ _gxf_vectors:
 
 _gxf_exc_sync:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _gxf_exc_entry
     bl exc_sync
@@ -168,6 +170,7 @@ _gxf_exc_sync:
 
 _gxf_serr:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _gxf_exc_entry
     bl exc_serr
@@ -225,6 +228,9 @@ _gxf_exc_return:
     ldp x26, x27, [sp], #16
     ldp x28, x29, [sp], #16
     ldr x30, [sp], #16
+
+    add sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
+
     isb
 
     gexit

src/hv_asm.S

@@ -1,5 +1,7 @@
 /* spDx-License-Identifier: MIT */
 
+#include "exception.h"
+
 .align 11
 .globl _hv_vectors_start
 _hv_vectors_start:
@@ -96,12 +98,16 @@ _hv_return:
     ldp x26, x27, [sp], #16
     ldp x28, x29, [sp], #16
     ldr x30, [sp], #16
+
+    add sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
+
     eret
 
 .globl _v_hv_sync
 .type _v_hv_sync, @function
 _v_hv_sync:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _hv_entry
     bl hv_exc_sync
@@ -112,6 +118,7 @@ _v_hv_sync:
 .type _v_hv_irq, @function
 _v_hv_irq:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _hv_entry
     bl hv_exc_irq
@@ -122,6 +129,7 @@ _v_hv_irq:
 .type _v_hv_fiq, @function
 _v_hv_fiq:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _hv_entry
     bl hv_exc_fiq
@@ -132,6 +140,7 @@ _v_hv_fiq:
 .type _v_hv_serr, @function
 _v_hv_serr:
     msr pan, #0
+    sub sp, sp, #(SIZEOF_EXC_INFO - 32 * 8)
     str x30, [sp, #-16]!
     bl _hv_entry
     bl hv_exc_serr

src/hv_exc.c

@@ -49,7 +49,7 @@ void hv_exc_proxy(u64 *regs, uartproxy_boot_reason_t reason, uartproxy_exc_code_
     u64 entry_time = mrs(CNTPCT_EL0);
 #endif
 
-    struct uartproxy_exc_info exc_info = {
+    struct exc_info exc_info = {
         .cpu_id = smp_id(),
         .spsr = hv_get_spsr(),
         .elr = hv_get_elr(),

src/hv_vm.c

@@ -5,6 +5,7 @@
 #include "hv.h"
 #include "assert.h"
 #include "cpu_regs.h"
+#include "exception.h"
 #include "iodev.h"
 #include "malloc.h"
 #include "smp.h"

src/uartproxy.h

@@ -32,22 +32,6 @@ typedef enum _uartproxy_event_type_t {
     EVT_IRQTRACE = 2,
 } uartproxy_event_type_t;
 
-struct uartproxy_exc_info {
-    u64 cpu_id;
-    u64 spsr;
-    u64 elr;
-    u64 esr;
-    u64 far;
-    u64 afsr1;
-    u64 regs[31];
-    u64 sp[3];
-    u64 mpidr;
-    u64 elr_phys;
-    u64 far_phys;
-    u64 sp_phys;
-    void *extra;
-};
-
 struct uartproxy_msg_start {
     u32 reason;
     u32 code;