c5dff4ffd3
On reboot or poweroff (machine_shutdown()) a call to smp_send_stop() is
made (to stop the others CPU's) when CONFIG_SMP=y.
arch/arm/kernel/process.c:
void machine_shutdown(void)
{
#ifdef CONFIG_SMP
smp_send_stop();
#endif
}
smp_send_stop() calls the function pointer smp_cross_call(), which is set
on the smp_init_cpus() function for OMAP processors.
arch/arm/mach-omap2/omap-smp.c:
void __init smp_init_cpus(void)
{
...
set_smp_cross_call(gic_raise_softirq);
...
}
But the ARM setup_arch() function only calls smp_init_cpus()
if CONFIG_SMP=y && is_smp().
arm/kernel/setup.c:
void __init setup_arch(char **cmdline_p)
{
...
#ifdef CONFIG_SMP
if (is_smp())
smp_init_cpus();
#endif
...
}
Newer OMAP CPU's are SMP machines so omap2plus_defconfig sets
CONFIG_SMP=y. Unfortunately on an OMAP UP machine is_smp()
returns false and smp_init_cpus() is never called and the
smp_cross_call() function remains NULL.
If the machine is rebooted or powered off, smp_send_stop() will
be called (since CONFIG_SMP=y) leading to the following error:
[ 42.815551] Restarting system.
[ 42.819030] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 42.827667] pgd = d7a74000
[ 42.830566] [00000000] *pgd=96ce7831, *pte=00000000, *ppte=00000000
[ 42.837249] Internal error: Oops: 80000007 [#1] SMP ARM
[ 42.842773] Modules linked in:
[ 42.846008] CPU: 0 Not tainted (3.5.0-rc3-next-20120622-00002-g62e87ba-dirty #44)
[ 42.854278] PC is at 0x0
[ 42.856994] LR is at smp_send_stop+0x4c/0xe4
[ 42.861511] pc : [<00000000>] lr : [<c00183a4>] psr: 60000013
[ 42.861511] sp : d6c85e70 ip : 00000000 fp : 00000000
[ 42.873626] r10: 00000000 r9 : d6c84000 r8 : 00000002
[ 42.879150] r7 : c07235a0 r6 : c06dd2d0 r5 : 000f4241 r4 : d6c85e74
[ 42.886047] r3 : 00000000 r2 : 00000000 r1 : 00000006 r0 : d6c85e74
[ 42.892944] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 42.900482] Control: 10c5387d Table: 97a74019 DAC: 00000015
[ 42.906555] Process reboot (pid: 1166, stack limit = 0xd6c842f8)
[ 42.912902] Stack: (0xd6c85e70 to 0xd6c86000)
[ 42.917510] 5e60: c07235a0 00000000 00000000 d6c84000
[ 42.926177] 5e80: 01234567 c00143d0 4321fedc c00511bc d6c85ebc 00000168 00000460 00000000
[ 42.934814] 5ea0: c1017950 a0000013 c1017900 d8014390 d7ec3858 c0498e48 c1017950 00000000
[ 42.943481] 5ec0: d6ddde10
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.. | ||
boot | ||
common | ||
configs | ||
include/asm | ||
kernel | ||
lib | ||
mach-at91 | ||
mach-bcmring | ||
mach-clps711x | ||
mach-cns3xxx | ||
mach-davinci | ||
mach-dove | ||
mach-ebsa110 | ||
mach-ep93xx | ||
mach-exynos | ||
mach-footbridge | ||
mach-gemini | ||
mach-h720x | ||
mach-highbank | ||
mach-imx | ||
mach-integrator | ||
mach-iop13xx | ||
mach-iop32x | ||
mach-iop33x | ||
mach-ixp4xx | ||
mach-kirkwood | ||
mach-ks8695 | ||
mach-l7200/include/mach | ||
mach-lpc32xx | ||
mach-mmp | ||
mach-msm | ||
mach-mv78xx0 | ||
mach-mxs | ||
mach-netx | ||
mach-nomadik | ||
mach-omap1 | ||
mach-omap2 | ||
mach-orion5x | ||
mach-picoxcell | ||
mach-pnx4008 | ||
mach-prima2 | ||
mach-pxa | ||
mach-realview | ||
mach-rpc | ||
mach-s3c24xx | ||
mach-s3c64xx | ||
mach-s3c2410 | ||
mach-s3c2412 | ||
mach-s3c2440 | ||
mach-s5p64x0 | ||
mach-s5pc100 | ||
mach-s5pv210 | ||
mach-sa1100 | ||
mach-shark | ||
mach-shmobile | ||
mach-spear3xx | ||
mach-spear6xx | ||
mach-spear13xx | ||
mach-tegra | ||
mach-u300 | ||
mach-ux500 | ||
mach-versatile | ||
mach-vexpress | ||
mach-vt8500 | ||
mach-w90x900 | ||
mach-zynq | ||
mm | ||
net | ||
nwfpe | ||
oprofile | ||
plat-iop | ||
plat-mxc | ||
plat-nomadik | ||
plat-omap | ||
plat-orion | ||
plat-pxa | ||
plat-s3c24xx | ||
plat-samsung | ||
plat-spear | ||
plat-versatile | ||
tools | ||
vfp | ||
Kconfig | ||
Kconfig-nommu | ||
Kconfig.debug | ||
Makefile |