| Message ID | 20190717080621.40424-6-yanaijie@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | implement KASLR for powerpc/fsl_booke/32 | expand |
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
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 <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) > 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 > > . >
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 + + mtspr SPRN_SRR0,r4 + mtspr SPRN_SRR1,r7 + isync + sync + rfi + /* * 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); #endif extern void loadcam_entry(unsigned int index); extern void loadcam_multi(int first_idx, int num, int tmp_idx);
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(+)