From: achandran@mvista.com (Arun Chandran)
To: linux-arm-kernel@lists.infradead.org
Subject: Kexec on arm64
Date: Tue, 29 Jul 2014 18:02:23 +0530 [thread overview]
Message-ID: <CAFdej00is0kC-1q5uMNJL5APL1WezdNBg0jASgwYamsg5NO_Tg@mail.gmail.com> (raw)
In-Reply-To: <1406592548.28348.49.camel@smoke>
Hi Geoff,
On Tue, Jul 29, 2014 at 5:39 AM, Geoff Levand <geoff@infradead.org> wrote:
> Hi,
>
> On Mon, 2014-07-28 at 16:38 +0100, Mark Rutland wrote:
>> On Mon, Jul 28, 2014 at 04:00:18PM +0100, Arun Chandran wrote:
>> > I have these changes to the code.
>> > flush_icache_range((unsigned long)reboot_code_buffer,
>> > - relocate_new_kernel_size);
>> > + (unsigned long)(reboot_code_buffer + relocate_new_kernel_size));
>
> Thanks, I introduced this in my last version in an attempt to clean up
> the code, but on studying setup_restart(), I wonder if we even need to
> do this icache flush here (see below).
>
>> > /*
>> > * Flush any data used by relocate_new_kernel in preparation for
>> > #########
>> > Passing of second variable to flush_icache_range() is wrong
>> > it expects an address not length.
>>
>> A simpler option would be to nuke the entire icache before branching to
>> the new image.
>
> flush_cache_all(), which is called by setup_restart(), does a 'ic
> ialluis'. The ARM says that this will invalidate all instruction caches
> for the inner shareable domain. Do we need something more?
>
>> > 2)
>> >
>> > #######
>> > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
>> > index 9ed7327..e3fc8d6 100644
>> > --- a/arch/arm64/kernel/process.c
>> > +++ b/arch/arm64/kernel/process.c
>> >
>> > @@ -84,12 +91,17 @@ void soft_restart(unsigned long addr)
>> > {
>> > typedef void (*phys_reset_t)(unsigned long);
>> > phys_reset_t phys_reset;
>> > + unsigned long jump_addr = addr;
>> > +
>> > + phys_reset = (phys_reset_t)virt_to_phys(cpu_reset);
>> > +
>> > + __flush_dcache_area(&jump_addr, 8);
>> > + __flush_dcache_area(&phys_reset, 8);
>>
>> Are these values really not getting stashed in registers?
>
> Looking at the disassembled code of soft_restart() from my compiler,
> addr is being saved on the stack over the call to setup_restart(), which
> I would expect it to do.
>
Yes my compiler also saves this in stack
>> If the compiler is spilling, then we have absolutely no guarantee about
>> any part of the stack. If that's the case, then we can't use the stack
>> at all. These need to be rewritten in asm if the compiler is spilling.
>
> I think we just need to put the restart addr in a variable and flush
> that to the PoC.
>
> Arun, I pushed out a fixed version of soft_restart(), so please try
> another UP + L3 boot.
>
The default code did not work.
It is working with the change below
###############
diff --git a/arch/arm64/kernel/machine_kexec.c
b/arch/arm64/kernel/machine_kexec.c
index 5632473..7c5f859 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -147,12 +147,17 @@ static bool kexec_is_dtb_user(const dtb_t *dtb)
/**
* kexec_list_walk - Helper to walk the kimage page list.
*/
-
+static int kexec_kernel_size;
+#define IMG_SIZE_NONE 0
+#define KERN_SIZE_FLAG 1
+#define DTB_SIZE_FLAG 2
static void kexec_list_walk(void *ctx, unsigned long kimage_head,
void (*cb)(void *ctx, unsigned int flag, void *addr, void *dest))
{
void *dest;
unsigned long *entry;
+ int imgsize_flag = IMG_SIZE_NONE;
+
for (entry = &kimage_head, dest = NULL; ; entry++) {
unsigned int flag = *entry & IND_FLAGS;
@@ -164,10 +169,18 @@ static void kexec_list_walk(void *ctx, unsigned
long kimage_head,
cb(ctx, flag, addr, NULL);
break;
case IND_DESTINATION:
+ if (imgsize_flag == IMG_SIZE_NONE) {
+ kexec_kernel_size = 0;
+ imgsize_flag = KERN_SIZE_FLAG;
+ } else if (imgsize_flag == KERN_SIZE_FLAG) {
+ imgsize_flag = DTB_SIZE_FLAG;
+ }
dest = addr;
cb(ctx, flag, addr, NULL);
break;
case IND_SOURCE:
+ if (imgsize_flag == KERN_SIZE_FLAG)
+ kexec_kernel_size++;
cb(ctx, flag, addr, dest);
dest += PAGE_SIZE;
break;
@@ -693,5 +706,20 @@ void machine_kexec(struct kimage *image)
kexec_list_walk(NULL, image->head, kexec_list_flush_cb);
+ /*
+ * Make sure virtual addresses of new kernel are flushed
+ * SZ_512K = TEXT_OFFSET
+ * kexec_kernel = kexec_kernel_size * PAGE_SIZE
+ * Don't know = (SZ_4M + SZ_1M)
+ * SZ_4M = not working
+ * SZ_6M = working
+ * SZ_8M = working
+ *
+ * so chose SZ_4M + SZ_1M; Don't know why this is required
+ * BSS, stack ??
+ *
+ */
+ __flush_dcache_area((void *)PAGE_OFFSET, SZ_512K +
(kexec_kernel_size * PAGE_SIZE) + SZ_4M + SZ_1M);
+
soft_restart(reboot_code_buffer_phys);
}
--Arun
next prev parent reply other threads:[~2014-07-29 12:32 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAFdej006OSyhgDcJ2iZdbjt+PtysN=i_+9Dr4GTmr=+t5yg4Kw@mail.gmail.com>
2014-07-15 17:04 ` Kexec on arm64 Geoff Levand
2014-07-16 17:57 ` Feng Kan
2014-07-16 23:04 ` Geoff Levand
2014-07-22 9:44 ` Arun Chandran
2014-07-22 13:25 ` Arun Chandran
2014-07-24 0:38 ` Geoff Levand
2014-07-24 9:36 ` Mark Rutland
2014-07-24 12:49 ` Arun Chandran
2014-07-25 0:17 ` Geoff Levand
2014-07-25 10:31 ` Arun Chandran
2014-07-25 10:36 ` Mark Rutland
2014-07-25 11:48 ` Arun Chandran
2014-07-25 12:14 ` Mark Rutland
2014-07-25 15:29 ` Arun Chandran
2014-07-26 0:18 ` Geoff Levand
2014-07-28 15:00 ` Arun Chandran
2014-07-28 15:38 ` Mark Rutland
2014-07-29 0:09 ` Geoff Levand
2014-07-29 9:10 ` Mark Rutland
2014-07-29 12:32 ` Arun Chandran [this message]
2014-07-29 13:35 ` Mark Rutland
2014-07-29 21:19 ` Geoff Levand
2014-07-30 7:22 ` Arun Chandran
2014-08-01 11:13 ` Arun Chandran
2014-08-03 14:47 ` Mark Rutland
2014-08-04 10:16 ` Arun Chandran
2014-08-04 11:35 ` Mark Rutland
2014-08-07 0:40 ` Geoff Levand
2014-08-07 9:59 ` Mark Rutland
2014-08-07 17:09 ` Geoff Levand
2014-08-04 17:21 ` Geoff Levand
2014-08-06 13:54 ` Arun Chandran
2014-08-06 15:51 ` Arun Chandran
2014-08-07 20:07 ` Geoff Levand
2014-08-08 5:46 ` Arun Chandran
2014-08-08 10:03 ` Arun Chandran
2014-08-12 5:42 ` Arun Chandran
2014-08-13 11:09 ` Arun Chandran
2014-08-26 22:32 ` Geoff Levand
2014-08-27 4:56 ` Arun Chandran
2014-07-30 5:46 ` Arun Chandran
2014-07-30 9:16 ` Mark Rutland
2014-07-30 7:01 ` Arun Chandran
2014-07-25 10:26 ` Arun Chandran
2014-07-25 11:29 ` Mark Rutland
2014-07-24 11:50 ` Arun Chandran
2014-07-30 3:26 ` Feng Kan
2014-07-24 0:10 ` Geoff Levand
2014-07-24 9:13 ` Mark Rutland
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