On 2019/7/29 19:08, Christophe Leroy wrote:
Le 17/07/2019 à 10:06, Jason Yan a écrit :
Add a new helper reloc_kernel_entry() to jump back to the start of the
new kernel. After we put the new kernel in a randomized place we can use
this new helper to enter the kernel and begin to relocate again.
Signed-off-by: Jason Yan <yanai...@huawei.com>
Cc: Diana Craciun <diana.crac...@nxp.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Christophe Leroy <christophe.le...@c-s.fr>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Kees Cook <keesc...@chromium.org>
---
arch/powerpc/kernel/head_fsl_booke.S | 16 ++++++++++++++++
arch/powerpc/mm/mmu_decl.h | 1 +
2 files changed, 17 insertions(+)
diff --git a/arch/powerpc/kernel/head_fsl_booke.S
b/arch/powerpc/kernel/head_fsl_booke.S
index a57d44638031..ce40f96dae20 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -1144,6 +1144,22 @@ _GLOBAL(create_tlb_entry)
sync
blr
+/*
+ * Return to the start of the relocated kernel and run again
+ * r3 - virtual address of fdt
+ * r4 - entry of the kernel
+ */
+_GLOBAL(reloc_kernel_entry)
+ mfmsr r7
+ li r8,(MSR_IS | MSR_DS)
+ andc r7,r7,r8
Instead of the li/andc, what about the following:
rlwinm r7, r7, 0, ~(MSR_IS | MSR_DS)
Good idea.
+
+ mtspr SPRN_SRR0,r4
+ mtspr SPRN_SRR1,r7
+ isync
+ sync
+ rfi
Are the isync/sync really necessary ? AFAIK, rfi is context synchronising.
I see some code with sync before rfi so I'm not sure. I will check this
and drop the isync/sync if it's true.
Thanks.
+
/*
* Create a tlb entry with the same effective and physical address as
* the tlb entry used by the current running code. But set the TS to 1.
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index d7737cf97cee..dae8e9177574 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -143,6 +143,7 @@ extern void adjust_total_lowmem(void);
extern int switch_to_as1(void);
extern void restore_to_as0(int esel, int offset, void *dt_ptr, int
bootcpu);
extern void create_tlb_entry(phys_addr_t phys, unsigned long virt,
int entry);
+extern void reloc_kernel_entry(void *fdt, int addr);
No new 'extern' please, see
https://openpower.xyz/job/snowpatch/job/snowpatch-linux-checkpatch/8125//artifact/linux/checkpatch.log
#endif
extern void loadcam_entry(unsigned int index);
extern void loadcam_multi(int first_idx, int num, int tmp_idx);
Christophe
.
