| Message ID | 20140109000219.GA6884@home.buserror.net (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Wed, Jan 08, 2014 at 06:02:19PM -0600, Scott Wood wrote: > On Wed, Jan 08, 2014 at 10:42:35AM +0800, Kevin Hao wrote: > > On Tue, Jan 07, 2014 at 05:46:04PM -0600, Scott Wood wrote: > > > Oh. I think it'd be more readable to do "offset = start - > > > memstart_addr" and add offset instead of subtracting it. > > > > Yes, I agree. The reason that I use "offset = memstart_addr - start" is that > > it seems "memstart_addr" is always greater than "start" when we are booting > > a kdump kernel with a kernel option like "crashkernel=64M@80M". :-) > > > > > > > > Also, offset should be phys_addr_t -- even if you don't expect to > > > support offsets greater than 4G on 32-bit, it's semantically the right > > > type to use. Plus, "int" would break if this code were ever used with > > > 64-bit. > > > > I thought about using phy_addr_t for the "offset" originally but gave it up > > for the following reasons: > > * It will not be greater than 4G. > > * We have to use the ugly #ifdef CONFIG_PHYS_64BIT in restore_to_as0(). > > * Need more registers for arguments for restore_to_as0(). > > > > Of course you can change it to phys_addr_t if you prefer. > > Here's the diff I made when applying (also changed the subf in patch 9 to > add) Looks fine to me. I also done a boot test and it works pretty well. Thanks Scott. Kevin
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S index 71e08df..b1f7edc 100644 --- a/arch/powerpc/kernel/head_fsl_booke.S +++ b/arch/powerpc/kernel/head_fsl_booke.S @@ -1251,7 +1251,7 @@ _GLOBAL(switch_to_as1) * Restore to the address space 0 and also invalidate the tlb entry created * by switch_to_as1. * r3 - the tlb entry which should be invalidated - * r4 - __pa(PAGE_OFFSET in AS0) - __pa(PAGE_OFFSET in AS1) + * r4 - __pa(PAGE_OFFSET in AS1) - __pa(PAGE_OFFSET in AS0) * r5 - device tree virtual address. If r4 is 0, r5 is ignored. */ _GLOBAL(restore_to_as0) @@ -1266,8 +1266,8 @@ _GLOBAL(restore_to_as0) * so we need calculate the right jump and device tree address based * on the offset passed by r4. */ - subf r9,r4,r9 - subf r5,r4,r5 + add r9,r9,r4 + add r5,r5,r4 2: mfmsr r7 li r8,(MSR_IS | MSR_DS) diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c index ce0c7d7..95deb9fd 100644 --- a/arch/powerpc/mm/fsl_booke_mmu.c +++ b/arch/powerpc/mm/fsl_booke_mmu.c @@ -291,7 +291,8 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) * and do a second relocation. */ if (start != memstart_addr) { - int n, offset = memstart_addr - start; + int n; + long offset = start - memstart_addr; is_second_reloc = 1; n = switch_to_as1(); @@ -299,7 +300,7 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) if (memstart_addr > start) map_mem_in_cams(0x4000000, CONFIG_LOWMEM_CAM_NUM); else - map_mem_in_cams_addr(start, PAGE_OFFSET - offset, + map_mem_in_cams_addr(start, PAGE_OFFSET + offset, 0x4000000, CONFIG_LOWMEM_CAM_NUM); restore_to_as0(n, offset, __va(dt_ptr)); /* We should never reach here */