parisc: Unbreak handling exceptions from kernel modules

Handling exceptions from modules never worked on parisc. It was just masked by the fact that exceptions from modules don't happen during normal use. When a module triggers an exception in get_user() we need to load the main kernel dp value before accessing the exception_data structure, and afterwards restore the original dp value of the module on exit.

Helge Deller committed 10 years ago

Commit 2ef4dfd1 parent ef72f314 files · +9 −0Browse files

Unified · Split

4 files

arch/parisc/include/asm/uaccess.h +1 −0
arch/parisc/kernel/asm-offsets.c +1 −0
arch/parisc/lib/fixup.S +6 −0
arch/parisc/mm/fault.c +1 −0

arch/parisc/include/asm/uaccess.h+1−0

@@ -77,6 +77,7 @@ struct exception_table_entry { · 76 unmodified lines
77	77	*/
78	78	struct exception_data {
79	79	unsigned long fault_ip;
	80	+ unsigned long fault_gp;
80	81	unsigned long fault_space;
81	82	unsigned long fault_addr;
82	83	};

arch/parisc/kernel/asm-offsets.c+1−0

@@ -299,6 +299,7 @@ int main(void) · 298 unmodified lines
299	299	#endif
300	300	BLANK();
301	301	DEFINE(EXCDATA_IP, offsetof(struct exception_data, fault_ip));
	302	+ DEFINE(EXCDATA_GP, offsetof(struct exception_data, fault_gp));
302	303	DEFINE(EXCDATA_SPACE, offsetof(struct exception_data, fault_space));
303	304	DEFINE(EXCDATA_ADDR, offsetof(struct exception_data, fault_addr));
304	305	BLANK();

arch/parisc/lib/fixup.S+6−0

@@ -26,6 +26,7 @@ · 25 unmodified lines
26	26
27	27	#ifdef CONFIG_SMP
28	28	.macro get_fault_ip t1 t2
	29	+ loadgp
29	30	addil LT%__per_cpu_offset,%r27
30	31	LDREG RT%__per_cpu_offset(%r1),\t1
31	32	/* t2 = smp_processor_id() */
@@ -40,14 +41,19 @@ · 8 unmodified lines
40	41	LDREG RT%exception_data(%r1),\t1
41	42	/* t1 = this_cpu_ptr(&exception_data) */
42	43	add,l \t1,\t2,\t1
	44	+ /* %r27 = t1->fault_gp - restore gp */
	45	+ LDREG EXCDATA_GP(\t1), %r27
43	46	/* t1 = t1->fault_ip */
44	47	LDREG EXCDATA_IP(\t1), \t1
45	48	.endm
46	49	#else
47	50	.macro get_fault_ip t1 t2
	51	+ loadgp
48	52	/* t1 = this_cpu_ptr(&exception_data) */
49	53	addil LT%exception_data,%r27
50	54	LDREG RT%exception_data(%r1),\t2
	55	+ /* %r27 = t2->fault_gp - restore gp */
	56	+ LDREG EXCDATA_GP(\t2), %r27
51	57	/* t1 = t2->fault_ip */
52	58	LDREG EXCDATA_IP(\t2), \t1
53	59	.endm

arch/parisc/mm/fault.c+1−0

@@ -145,6 +145,7 @@ int fixup_exception(struct pt_regs *regs) · 144 unmodified lines
145	145	struct exception_data *d;
146	146	d = this_cpu_ptr(&exception_data);
147	147	d->fault_ip = regs->iaoq[0];
	148	+ d->fault_gp = regs->gr[27];
148	149	d->fault_space = regs->isr;
149	150	d->fault_addr = regs->ior;
150	151