A few patches for 2.4.x for Alpha...
I seem to be VERY unsuccessful in getting patches into the kernel anymore,
so I figured I'd try sending them to you first due to your high success
rate :-)
Attached is a patch that does three things:
* drivers/char/rtc.c:
Removes MIPS DECstation epoch support for non-MIPS machines and adds
standard PC (1900) epoch support in its place (which will act
as a pre-2000 VMS epoch support patch as well). It also adds post-2000
VMS epoch support.
My testing so far has shown that, with this patch, I can NEVER seem to
guess the year incorrectly, regardless of where it was set.
* arch/alpha/kernel/smp.c:
Removed smp_tune_scheduling() function and the cacheflush_time var
since they weren't being used. I also ran into a few machine types
where this function being executed on an SMP machine during boot caused
an oops. I didn't bother looking into it too much (since the entire
purpose of the function was to determine cacheflush_time, which is
unused in the 2.4 scheduler code), but deleting the function works in
getting SMP systems to boot 2.4 SMP kernels.
* arch/alpha/kernel/entry.S:
arch/alpha/kernel/proto.h:
arch/alpha/kernel/traps.c:
This patch is from Daniel Potts (a coworker) who found out that, if the
user invokes the crlfen PALcode call, the kernel is unable to cope with
not having access to the FP registers. He wrote two asm stubs to
basically skip FP register access in these cases. The problem was found
to be extremely rare, but definite is a way for a user (non-root) to
crash a running Alpha.
There's also a small patch from Rick Gorton (also a coworker) that
allows an illop trap to be handled correctly by the kernel.
If you have any questions about the patches, feel free to ask :-) I'm
extremely concerned about the problems that Daniel found (with the ability
of a common user to crash a running machine by just disabling FP
registers), so the sooner this goes in, the better off we all will be :-)
Thanks!
C
diff -burN linux-2.4.7/arch/alpha/kernel/entry.S linux-247-patched/arch/alpha/kernel/entry.S
--- linux-2.4.7/arch/alpha/kernel/entry.S Thu Jul 26 16:45:31 2001
+++ linux-247-patched/arch/alpha/kernel/entry.S Wed Aug 1 17:28:50 2001
@@ -290,6 +290,8 @@
.end __kernel_execve
.align 3
+.globl do_switch_fp_start
+.globl do_switch_fp_end
.ent do_switch_stack
do_switch_stack:
lda $30,-SWITCH_STACK_SIZE($30)
@@ -301,6 +303,7 @@
stq $14,40($30)
stq $15,48($30)
stq $26,56($30)
+do_switch_fp_start:
stt $f0,64($30)
stt $f1,72($30)
stt $f2,80($30)
@@ -335,10 +338,13 @@
stt $f30,304($30)
stt $f0,312($30) # save fpcr in slot of $f31
ldt $f0,64($30) # dont let "do_switch_stack" change fp state.
+do_switch_fp_end:
ret $31,($1),1
.end do_switch_stack
.align 3
+.globl undo_switch_fp_start
+.globl undo_switch_fp_end
.ent undo_switch_stack
undo_switch_stack:
ldq $9,0($30)
@@ -349,6 +355,7 @@
ldq $14,40($30)
ldq $15,48($30)
ldq $26,56($30)
+undo_switch_fp_start:
ldt $f30,312($30) # get saved fpcr
ldt $f0,64($30)
ldt $f1,72($30)
@@ -382,6 +389,7 @@
ldt $f28,288($30)
ldt $f29,296($30)
ldt $f30,304($30)
+undo_switch_fp_end:
lda $30,SWITCH_STACK_SIZE($30)
ret $31,($1),1
.end undo_switch_stack
diff -burN linux-2.4.7/arch/alpha/kernel/proto.h linux-247-patched/arch/alpha/kernel/proto.h
--- linux-2.4.7/arch/alpha/kernel/proto.h Thu Jul 26 16:16:37 2001
+++ linux-247-patched/arch/alpha/kernel/proto.h Wed Aug 1 17:28:54 2001
@@ -134,6 +134,11 @@
extern void entUna(void);
extern void entDbg(void);
+extern void do_switch_fp_start(void);
+extern void do_switch_fp_end(void);
+extern void undo_switch_fp_start(void);
+extern void undo_switch_fp_end(void);
+
/* process.c */
extern void cpu_idle(void) __attribute__((noreturn));
diff -burN linux-2.4.7/arch/alpha/kernel/smp.c linux-247-patched/arch/alpha/kernel/smp.c
--- linux-2.4.7/arch/alpha/kernel/smp.c Thu Jul 26 16:41:17 2001
+++ linux-247-patched/arch/alpha/kernel/smp.c Wed Aug 1 17:28:58 2001
@@ -72,7 +72,6 @@
int smp_num_probed; /* Internal processor count */
int smp_num_cpus = 1; /* Number that came online. */
int smp_threads_ready; /* True once the per process idle is forked. */
-cycles_t cacheflush_time;
int __cpu_number_map[NR_CPUS];
int __cpu_logical_map[NR_CPUS];
@@ -205,62 +204,6 @@
/*
- * Rough estimation for SMP scheduling, this is the number of cycles it
- * takes for a fully memory-limited process to flush the SMP-local cache.
- *
- * We are not told how much cache there is, so we have to guess.
- */
-static void __init
-smp_tune_scheduling (void)
-{
- struct percpu_struct *cpu;
- unsigned long on_chip_cache;
- unsigned long freq;
-
- cpu = (struct percpu_struct*)((char*)hwrpb + hwrpb->processor_offset);
- switch (cpu->type)
- {
- case EV45_CPU:
- on_chip_cache = 16 + 16;
- break;
-
- case EV5_CPU:
- case EV56_CPU:
- on_chip_cache = 8 + 8 + 96;
- break;
-
- case PCA56_CPU:
- on_chip_cache = 16 + 8;
- break;
-
- case EV6_CPU:
- case EV67_CPU:
- on_chip_cache = 64 + 64;
- break;
-
- default:
- on_chip_cache = 8 + 8;
- break;
- }
-
- freq = hwrpb->cycle_freq ? : est_cycle_freq;
-
-#if 0
- /* Magic estimation stolen from x86 port. */
- cacheflush_time = freq / 1024L * on_chip_cache / 5000L;
-
- printk("Using heuristic of %d cycles.\n",
- cacheflush_time);
-#else
- /* Magic value to force potential preemption of other CPUs. */
- cacheflush_time = INT_MAX;
-
- printk("Using heuristic of %d cycles.\n",
- cacheflush_time);
-#endif
-}
-
-/*
* Send a message to a secondary's console. "START" is one such
* interesting message. ;-)
*/
@@ -599,7 +542,6 @@
current->processor = boot_cpuid;
smp_store_cpu_info(boot_cpuid);
- smp_tune_scheduling();
smp_setup_percpu_timer(boot_cpuid);
init_idle();
diff -burN linux-2.4.7/arch/alpha/kernel/traps.c linux-247-patched/arch/alpha/kernel/traps.c
--- linux-2.4.7/arch/alpha/kernel/traps.c Thu Jul 26 16:45:31 2001
+++ linux-247-patched/arch/alpha/kernel/traps.c Wed Aug 1 17:29:01 2001
@@ -188,6 +188,23 @@
unsigned long a2, unsigned long a3, unsigned long a4,
unsigned long a5, struct pt_regs regs)
{
+ if (type == 3 && !(regs.ps & 8) ) {
+ /*
+ * Handle a rare case where the user has disabled floating
+ * point using the clrfen PALcall and the kernel is attempting
+ * to view floating point state. This happens in two asm stubs:
+ * do_switch_stack and undo_switch_stack.
+ * If this is the case, we modify the return value to pass
+ * over this section and resume from there.
+ */
+ if (regs.pc == (unsigned long) do_switch_fp_start) {
+ regs.pc = (unsigned long) do_switch_fp_end;
+ return;
+ } else if (regs.pc == (unsigned long) undo_switch_fp_start) {
+ regs.pc = (unsigned long) undo_switch_fp_end;
+ return;
+ }
+ }
die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
®s, type, 0);
@@ -252,6 +269,10 @@
if (alpha_fp_emul(regs.pc-4))
return;
}
+ send_sig(SIGILL, current, 1);
+ break;
+
+ case 5: /* illop */
send_sig(SIGILL, current, 1);
break;
diff -burN linux-2.4.7/drivers/char/rtc.c linux-247-patched/drivers/char/rtc.c
--- linux-2.4.7/drivers/char/rtc.c Thu Jul 26 16:41:08 2001
+++ linux-247-patched/drivers/char/rtc.c Wed Aug 1 17:48:57 2001
@@ -710,15 +710,24 @@
if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
BCD_TO_BIN(year); /* This should never happen... */
- if (year >= 20 && year < 48) {
+ if (year < 20) {
+ epoch = 2000;
+ guess = "SRM (post-2000)";
+ } else if (year >= 20 && year < 48) {
epoch = 1980;
guess = "ARC console";
} else if (year >= 48 && year < 70) {
epoch = 1952;
guess = "Digital UNIX";
+#if defined(__mips__)
} else if (year >= 70 && year < 100) {
epoch = 1928;
guess = "Digital DECstation";
+#else
+ } else if (year >= 70) {
+ epoch = 1900;
+ guess = "Standard PC (1900)";
+#endif
}
if (guess)
printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", guess, epoch);
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