Messages in this thread Patch in this message | | | Subject | Re: [RFC PATCH 05/10] powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper | From | Christophe Leroy <> | Date | Mon, 29 Jul 2019 13:08:08 +0200 |
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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 <yanaijie@huawei.com> > Cc: Diana Craciun <diana.craciun@nxp.com> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Christophe Leroy <christophe.leroy@c-s.fr> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Kees Cook <keescook@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)
> + > + mtspr SPRN_SRR0,r4 > + mtspr SPRN_SRR1,r7 > + isync > + sync > + rfi
Are the isync/sync really necessary ? AFAIK, rfi is context synchronising.
> + > /* > * 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
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