Scott Wood <o...@buserror.net> writes:
> This contains KASLR support for book3e 32-bit.
>
> The following changes since commit 612ee81b9461475b5a5612c2e8d71559dd3c7920:
>
> powerpc/papr_scm: Fix an off-by-one check in papr_scm_meta_{get, set}
> (2019-10-10 20:15:53 +1100)
>
> are available in the Git repository at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux.git next
>
> for you to fetch changes up to 9df1ef3f1376ec5d3a1b51a4546c94279bcd88ca:
>
> powerpc/fsl_booke/32: Document KASLR implementation (2019-10-21 16:09:16
> -0500)
>
> ----------------------------------------------------------------
> Jason Yan (12):
> powerpc: unify definition of M_IF_NEEDED
> powerpc: move memstart_addr and kernstart_addr to init-common.c
> powerpc: introduce kernstart_virt_addr to store the kernel base
> powerpc/fsl_booke/32: introduce create_kaslr_tlb_entry() helper
> powerpc/fsl_booke/32: introduce reloc_kernel_entry() helper
> powerpc/fsl_booke/32: implement KASLR infrastructure
This commit breaks booting on the qemu mac99 machine, using pmac32_defconfig.
$ qemu-system-ppc -nographic -vga none -M mac99 -m 1G -kernel vmlinux
>> =============================================================
>> OpenBIOS 1.1 [Oct 5 2018 08:21]
>> Configuration device id QEMU version 1 machine id 1
>> CPUs: 1
>> Memory: 1024M
>> UUID: 00000000-0000-0000-0000-000000000000
>> CPU type PowerPC,G4
milliseconds isn't unique.
Welcome to OpenBIOS v1.1 built on Oct 5 2018 08:21
>> [ppc] Kernel already loaded (0x01000000 + 0x009d2920) (initrd 0x00000000 +
0x00000000)
>> [ppc] Kernel command line:
>> switching to new context:
OF stdout device is: /pci@f2000000/mac-io@c/escc@13000/ch-a@13020
Preparing to boot Linux version 5.4.0-rc2-gcc49-05398-g4e1bb50
(michael@alpine1-p1) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #30
Wed Nov 13 15:07:39 AEDT 2019
Detected machine type: 00000400
command line:
memory layout at init:
memory_limit : 00000000 (16 MB aligned)
alloc_bottom : 019d7000
alloc_top : 30000000
alloc_top_hi : 40000000
rmo_top : 30000000
ram_top : 40000000
copying OF device tree...
Building dt strings...
Building dt structure...
Device tree strings 0x019d8000 -> 0x019d70a4
Device tree struct 0x019d9000 -> 0x3fde7eb0
Quiescing Open Firmware ...
Booting Linux via __start() @ 0x01000000 ...
And no output after that.
The problematic hunk is the change to early_32.c:
diff --git a/arch/powerpc/kernel/early_32.c b/arch/powerpc/kernel/early_32.c
index 3482118ffe76..6f8689d7ca7b 100644
--- a/arch/powerpc/kernel/early_32.c
+++ b/arch/powerpc/kernel/early_32.c
@@ -22,7 +22,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
unsigned long offset = reloc_offset();
/* First zero the BSS */
- memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
+ if (kernstart_virt_addr == KERNELBASE)
+ memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
/*
* Identify the CPU type and fix up code sections
@@ -32,5 +33,5 @@ notrace unsigned long __init early_init(unsigned long dt_ptr)
apply_feature_fixups();
- return KERNELBASE + offset;
+ return kernstart_virt_addr + offset;
}
It needs to use PTRRELOC() for the kernstart_virt_addr accesses.
I've made that change and squashed it into the series. I've pushed that
as a branch to here:
https://github.com/linuxppc/linux/commits/topic/kaslr-book3e32
That boots for me on qemu mac99.
Jason can you please test it on your setup with KASLR enabled to make
sure it still works.
cheers
