Jan Beulich
2007-Dec-10 09:29 UTC
[Xen-devel] [PATCH] x86: eliminate (unused) return value from exception handling routines
(Hunk 4 will only apply cleanly on top of the previously sent
gdprintk() cleanup patch.)
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Index: 2007-12-10/xen/arch/x86/traps.c
==================================================================---
2007-12-10.orig/xen/arch/x86/traps.c 2007-12-10 09:24:04.000000000 +0100
+++ 2007-12-10/xen/arch/x86/traps.c 2007-12-10 09:25:55.000000000 +0100
@@ -86,12 +86,11 @@ idt_entry_t *idt_tables[NR_CPUS] __read_
#define DECLARE_TRAP_HANDLER(_name) \
asmlinkage void _name(void); \
-asmlinkage int do_ ## _name(struct cpu_user_regs *regs)
+asmlinkage void do_ ## _name(struct cpu_user_regs *regs)
-asmlinkage void nmi(void);
-asmlinkage void machine_check(void);
DECLARE_TRAP_HANDLER(divide_error);
DECLARE_TRAP_HANDLER(debug);
+DECLARE_TRAP_HANDLER(nmi);
DECLARE_TRAP_HANDLER(int3);
DECLARE_TRAP_HANDLER(overflow);
DECLARE_TRAP_HANDLER(bounds);
@@ -105,6 +104,7 @@ DECLARE_TRAP_HANDLER(general_protection)
DECLARE_TRAP_HANDLER(page_fault);
DECLARE_TRAP_HANDLER(coprocessor_error);
DECLARE_TRAP_HANDLER(simd_coprocessor_error);
+DECLARE_TRAP_HANDLER(machine_check);
DECLARE_TRAP_HANDLER(alignment_check);
DECLARE_TRAP_HANDLER(spurious_interrupt_bug);
@@ -382,7 +382,7 @@ asmlinkage void fatal_trap(int trapnr, s
(regs->eflags & X86_EFLAGS_IF) ? "" : ", IN
INTERRUPT CONTEXT");
}
-static int do_guest_trap(
+static void do_guest_trap(
int trapnr, const struct cpu_user_regs *regs, int use_error_code)
{
struct vcpu *v = current;
@@ -411,8 +411,6 @@ static int do_guest_trap(
gdprintk(XENLOG_WARNING, "Unhandled %s fault/trap [#%d] "
"on VCPU %d [ec=%04x]\n",
trapstr(trapnr), trapnr, v->vcpu_id, regs->error_code);
-
- return 0;
}
static void instruction_done(
@@ -477,7 +475,7 @@ asmlinkage int set_guest_nmi_trapbounce(
return !null_trap_bounce(v, tb);
}
-static inline int do_trap(
+static inline void do_trap(
int trapnr, struct cpu_user_regs *regs, int use_error_code)
{
unsigned long fixup;
@@ -485,14 +483,17 @@ static inline int do_trap(
DEBUGGER_trap_entry(trapnr, regs);
if ( guest_mode(regs) )
- return do_guest_trap(trapnr, regs, use_error_code);
+ {
+ do_guest_trap(trapnr, regs, use_error_code);
+ return;
+ }
if ( likely((fixup = search_exception_table(regs->eip)) != 0) )
{
dprintk(XENLOG_ERR, "Trap %d: %p -> %p\n",
trapnr, _p(regs->eip), _p(fixup));
regs->eip = fixup;
- return 0;
+ return;
}
DEBUGGER_trap_fatal(trapnr, regs);
@@ -501,19 +502,18 @@ static inline int do_trap(
panic("FATAL TRAP: vector = %d (%s)\n"
"[error_code=%04x]\n",
trapnr, trapstr(trapnr), regs->error_code);
- return 0;
}
#define DO_ERROR_NOCODE(trapnr, name) \
-asmlinkage int do_##name(struct cpu_user_regs *regs) \
+asmlinkage void do_##name(struct cpu_user_regs *regs) \
{ \
- return do_trap(trapnr, regs, 0); \
+ do_trap(trapnr, regs, 0); \
}
#define DO_ERROR(trapnr, name) \
-asmlinkage int do_##name(struct cpu_user_regs *regs) \
+asmlinkage void do_##name(struct cpu_user_regs *regs) \
{ \
- return do_trap(trapnr, regs, 1); \
+ do_trap(trapnr, regs, 1); \
}
DO_ERROR_NOCODE(TRAP_divide_error, divide_error)
@@ -714,20 +714,20 @@ static int emulate_forced_invalid_op(str
return EXCRET_fault_fixed;
}
-asmlinkage int do_invalid_op(struct cpu_user_regs *regs)
+asmlinkage void do_invalid_op(struct cpu_user_regs *regs)
{
struct bug_frame bug;
struct bug_frame_str bug_str;
char *filename, *predicate, *eip = (char *)regs->eip;
- int rc, id, lineno;
+ int id, lineno;
DEBUGGER_trap_entry(TRAP_invalid_op, regs);
if ( likely(guest_mode(regs)) )
{
- if ( (rc = emulate_forced_invalid_op(regs)) != 0 )
- return rc;
- return do_guest_trap(TRAP_invalid_op, regs, 0);
+ if ( !emulate_forced_invalid_op(regs) )
+ do_guest_trap(TRAP_invalid_op, regs, 0);
+ return;
}
if ( !is_kernel(eip) ||
@@ -743,7 +743,7 @@ asmlinkage int do_invalid_op(struct cpu_
{
show_execution_state(regs);
regs->eip = (unsigned long)eip;
- return EXCRET_fault_fixed;
+ return;
}
/* WARN, BUG or ASSERT: decode the filename pointer and line number. */
@@ -761,7 +761,7 @@ asmlinkage int do_invalid_op(struct cpu_
printk("Xen WARN at %.50s:%d\n", filename, lineno);
show_execution_state(regs);
regs->eip = (unsigned long)eip;
- return EXCRET_fault_fixed;
+ return;
}
if ( id == BUGFRAME_bug )
@@ -792,10 +792,9 @@ asmlinkage int do_invalid_op(struct cpu_
DEBUGGER_trap_fatal(TRAP_invalid_op, regs);
show_execution_state(regs);
panic("FATAL TRAP: vector = %d (invalid opcode)\n",
TRAP_invalid_op);
- return 0;
}
-asmlinkage int do_int3(struct cpu_user_regs *regs)
+asmlinkage void do_int3(struct cpu_user_regs *regs)
{
DEBUGGER_trap_entry(TRAP_int3, regs);
@@ -806,7 +805,7 @@ asmlinkage int do_int3(struct cpu_user_r
panic("FATAL TRAP: vector = 3 (Int3)\n");
}
- return do_guest_trap(TRAP_int3, regs, 0);
+ do_guest_trap(TRAP_int3, regs, 0);
}
asmlinkage void do_machine_check(struct cpu_user_regs *regs)
@@ -1065,10 +1064,9 @@ static int fixup_page_fault(unsigned lon
* Bit 3: Reserved bit violation
* Bit 4: Instruction fetch
*/
-asmlinkage int do_page_fault(struct cpu_user_regs *regs)
+asmlinkage void do_page_fault(struct cpu_user_regs *regs)
{
unsigned long addr, fixup;
- int rc;
addr = read_cr2();
@@ -1076,19 +1074,19 @@ asmlinkage int do_page_fault(struct cpu_
perfc_incr(page_faults);
- if ( unlikely((rc = fixup_page_fault(addr, regs)) != 0) )
- return rc;
+ if ( unlikely(fixup_page_fault(addr, regs) != 0) )
+ return;
if ( unlikely(!guest_mode(regs)) )
{
if ( spurious_page_fault(addr, regs) )
- return EXCRET_not_a_fault;
+ return;
if ( likely((fixup = search_exception_table(regs->eip)) != 0) )
{
perfc_incr(copy_user_faults);
regs->eip = fixup;
- return 0;
+ return;
}
DEBUGGER_trap_fatal(TRAP_page_fault, regs);
@@ -1102,7 +1100,6 @@ asmlinkage int do_page_fault(struct cpu_
}
propagate_page_fault(addr, regs->error_code);
- return 0;
}
/*
@@ -1351,7 +1348,7 @@ void (*pv_post_outb_hook)(unsigned int p
if ( (_rc = copy_from_user(&_x, (type *)_ptr, sizeof(_x))) != 0 )
\
{ \
propagate_page_fault(_ptr + sizeof(_x) - _rc, 0); \
- return EXCRET_fault_fixed; \
+ goto skip; \
} \
(eip) += sizeof(_x); _x; })
@@ -2010,6 +2007,7 @@ static int emulate_privileged_op(struct
done:
instruction_done(regs, eip, bpmatch);
+ skip:
return EXCRET_fault_fixed;
fail:
@@ -2023,7 +2021,7 @@ static inline int check_stack_limit(unsi
(!(ar & _SEGMENT_EC) ? (esp - 1) <= limit : (esp - decr)
> limit));
}
-static int emulate_gate_op(struct cpu_user_regs *regs)
+static void emulate_gate_op(struct cpu_user_regs *regs)
{
#ifdef __x86_64__
struct vcpu *v = current;
@@ -2036,9 +2034,15 @@ static int emulate_gate_op(struct cpu_us
if ( !read_gate_descriptor(regs->error_code, v, &sel, &off,
&ar) ||
((ar >> 13) & 3) < (regs->cs & 3) ||
(ar & _SEGMENT_TYPE) != 0xc00 )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
if ( !(ar & _SEGMENT_P) )
- return do_guest_trap(TRAP_no_segment, regs, 1);
+ {
+ do_guest_trap(TRAP_no_segment, regs, 1);
+ return;
+ }
dpl = (ar >> 13) & 3;
nparm = ar & 0x1f;
@@ -2050,7 +2054,10 @@ static int emulate_gate_op(struct cpu_us
!(ar & _SEGMENT_S) ||
!(ar & _SEGMENT_P) ||
!(ar & _SEGMENT_CODE) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
op_bytes = op_default = ar & _SEGMENT_DB ? 4 : 2;
ad_default = ad_bytes = op_default;
@@ -2199,7 +2206,9 @@ static int emulate_gate_op(struct cpu_us
if ( jump < 0 )
{
fail:
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ skip:
+ return;
}
if ( (opnd_sel != regs->cs &&
@@ -2207,7 +2216,10 @@ static int emulate_gate_op(struct cpu_us
!(ar & _SEGMENT_S) ||
!(ar & _SEGMENT_P) ||
((ar & _SEGMENT_CODE) && !(ar & _SEGMENT_WR)) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
opnd_off += op_bytes;
#define ad_default ad_bytes
@@ -2215,7 +2227,10 @@ static int emulate_gate_op(struct cpu_us
#undef ad_default
ASSERT((opnd_sel & ~3) == regs->error_code);
if ( dpl < (opnd_sel & 3) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
if ( !read_descriptor(sel, v, regs, &base, &limit, &ar, 0) ||
!(ar & _SEGMENT_S) ||
@@ -2225,17 +2240,20 @@ static int emulate_gate_op(struct cpu_us
((ar >> 13) & 3) != (regs->cs & 3)) )
{
regs->error_code = sel;
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
}
if ( !(ar & _SEGMENT_P) )
{
regs->error_code = sel;
- return do_guest_trap(TRAP_no_segment, regs, 1);
+ do_guest_trap(TRAP_no_segment, regs, 1);
+ return;
}
if ( off > limit )
{
regs->error_code = 0;
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
}
if ( !jump )
@@ -2251,7 +2269,7 @@ static int emulate_gate_op(struct cpu_us
{ \
propagate_page_fault((unsigned long)(stkp + 1) - rc, \
PFEC_write_access); \
- return 0; \
+ return; \
} \
} while ( 0 )
@@ -2260,7 +2278,10 @@ static int emulate_gate_op(struct cpu_us
sel |= (ar >> 13) & 3;
/* Inner stack known only for kernel ring. */
if ( (sel & 3) != GUEST_KERNEL_RPL(v->domain) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
esp = v->arch.guest_context.kernel_sp;
ss = v->arch.guest_context.kernel_ss;
if ( (ss & 3) != (sel & 3) ||
@@ -2271,17 +2292,22 @@ static int emulate_gate_op(struct cpu_us
!(ar & _SEGMENT_WR) )
{
regs->error_code = ss & ~3;
- return do_guest_trap(TRAP_invalid_tss, regs, 1);
+ do_guest_trap(TRAP_invalid_tss, regs, 1);
+ return;
}
if ( !(ar & _SEGMENT_P) ||
!check_stack_limit(ar, limit, esp, (4 + nparm) * 4) )
{
regs->error_code = ss & ~3;
- return do_guest_trap(TRAP_stack_error, regs, 1);
+ do_guest_trap(TRAP_stack_error, regs, 1);
+ return;
}
stkp = (unsigned int *)(unsigned long)((unsigned int)base + esp);
if ( !compat_access_ok(stkp - 4 - nparm, (4 + nparm) * 4) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
push(regs->ss);
push(regs->esp);
if ( nparm )
@@ -2297,7 +2323,10 @@ static int emulate_gate_op(struct cpu_us
return do_guest_trap(TRAP_gp_fault, regs, 1);
ustkp = (unsigned int *)(unsigned long)((unsigned int)base +
regs->_esp + nparm * 4);
if ( !compat_access_ok(ustkp - nparm, nparm * 4) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
do
{
unsigned int parm;
@@ -2307,7 +2336,7 @@ static int emulate_gate_op(struct cpu_us
if ( rc )
{
propagate_page_fault((unsigned long)(ustkp + 1) - rc,
0);
- return 0;
+ return;
}
push(parm);
} while ( --nparm );
@@ -2320,15 +2349,22 @@ static int emulate_gate_op(struct cpu_us
ss = regs->ss;
if ( !read_descriptor(ss, v, regs, &base, &limit, &ar,
0) ||
((ar >> 13) & 3) != (sel & 3) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
if ( !check_stack_limit(ar, limit, esp, 2 * 4) )
{
regs->error_code = 0;
- return do_guest_trap(TRAP_stack_error, regs, 1);
+ do_guest_trap(TRAP_stack_error, regs, 1);
+ return;
}
stkp = (unsigned int *)(unsigned long)((unsigned int)base + esp);
if ( !compat_access_ok(stkp - 2, 2 * 4) )
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ {
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
+ }
}
push(regs->cs);
push(eip);
@@ -2342,11 +2378,9 @@ static int emulate_gate_op(struct cpu_us
regs->cs = sel;
instruction_done(regs, off, 0);
#endif
-
- return 0;
}
-asmlinkage int do_general_protection(struct cpu_user_regs *regs)
+asmlinkage void do_general_protection(struct cpu_user_regs *regs)
{
struct vcpu *v = current;
unsigned long fixup;
@@ -2388,18 +2422,22 @@ asmlinkage int do_general_protection(str
if ( permit_softint(TI_GET_DPL(ti), v, regs) )
{
regs->eip += 2;
- return do_guest_trap(vector, regs, 0);
+ do_guest_trap(vector, regs, 0);
+ return;
}
}
else if ( is_pv_32on64_vcpu(v) && regs->error_code )
- return emulate_gate_op(regs);
+ {
+ emulate_gate_op(regs);
+ return;
+ }
/* Emulate some simple privileged and I/O instructions. */
if ( (regs->error_code == 0) &&
emulate_privileged_op(regs) )
{
trace_trap_one_addr(TRC_PV_EMULATE_PRIVOP, regs->eip);
- return 0;
+ return;
}
#if defined(__i386__)
@@ -2408,12 +2446,13 @@ asmlinkage int do_general_protection(str
gpf_emulate_4gb(regs) )
{
TRACE_1D(TRC_PV_EMULATE_4GB, regs->eip);
- return 0;
+ return;
}
#endif
/* Pass on GPF as is. */
- return do_guest_trap(TRAP_gp_fault, regs, 1);
+ do_guest_trap(TRAP_gp_fault, regs, 1);
+ return;
gp_in_kernel:
@@ -2422,7 +2461,7 @@ asmlinkage int do_general_protection(str
dprintk(XENLOG_INFO, "GPF (%04x): %p -> %p\n",
regs->error_code, _p(regs->eip), _p(fixup));
regs->eip = fixup;
- return 0;
+ return;
}
DEBUGGER_trap_fatal(TRAP_gp_fault, regs);
@@ -2430,7 +2469,6 @@ asmlinkage int do_general_protection(str
hardware_gp:
show_execution_state(regs);
panic("GENERAL PROTECTION FAULT\n[error_code=%04x]\n",
regs->error_code);
- return 0;
}
static void nmi_softirq(void)
@@ -2550,7 +2588,7 @@ void unset_nmi_callback(void)
nmi_callback = dummy_nmi_callback;
}
-asmlinkage int do_device_not_available(struct cpu_user_regs *regs)
+asmlinkage void do_device_not_available(struct cpu_user_regs *regs)
{
struct vcpu *curr = current;
@@ -2566,10 +2604,10 @@ asmlinkage int do_device_not_available(s
else
TRACE_0D(TRC_PV_MATH_STATE_RESTORE);
- return EXCRET_fault_fixed;
+ return;
}
-asmlinkage int do_debug(struct cpu_user_regs *regs)
+asmlinkage void do_debug(struct cpu_user_regs *regs)
{
struct vcpu *v = current;
@@ -2609,16 +2647,16 @@ asmlinkage int do_debug(struct cpu_user_
v->arch.guest_context.debugreg[6] = read_debugreg(6);
ler_enable();
- return do_guest_trap(TRAP_debug, regs, 0);
+ do_guest_trap(TRAP_debug, regs, 0);
+ return;
out:
ler_enable();
- return EXCRET_not_a_fault;
+ return;
}
-asmlinkage int do_spurious_interrupt_bug(struct cpu_user_regs *regs)
+asmlinkage void do_spurious_interrupt_bug(struct cpu_user_regs *regs)
{
- return EXCRET_not_a_fault;
}
void set_intr_gate(unsigned int n, void *addr)
Index: 2007-12-10/xen/include/asm-x86/debugger.h
==================================================================---
2007-12-10.orig/xen/include/asm-x86/debugger.h 2007-04-02 12:16:26.000000000
+0200
+++ 2007-12-10/xen/include/asm-x86/debugger.h 2007-12-10 09:25:07.000000000
+0100
@@ -35,9 +35,9 @@
/* The main trap handlers use these helper macros which include early bail. */
#define DEBUGGER_trap_entry(_v, _r) \
- if ( debugger_trap_entry(_v, _r) ) return EXCRET_fault_fixed;
+ if ( debugger_trap_entry(_v, _r) ) return;
#define DEBUGGER_trap_fatal(_v, _r) \
- if ( debugger_trap_fatal(_v, _r) ) return EXCRET_fault_fixed;
+ if ( debugger_trap_fatal(_v, _r) ) return;
#if defined(CRASH_DEBUG)
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