On 06/20/2016 06:59 PM, Thomas Huth wrote:
On 20.06.2016 17:42, Cédric Le Goater wrote:
On 06/20/2016 03:26 PM, Alexander Graf wrote:
On 06/20/2016 02:59 PM, Cédric Le Goater wrote:
On 06/20/2016 11:49 AM, Mark Cave-Ayland wrote:
On 20/06/16 10:33, Alexander Graf wrote:
On 06/20/2016 11:32 AM, Cédric Le Goater wrote: > On 06/20/2016 09:39 AM, Alexander Graf wrote: >> On 20.06.16 09:34, Cédric Le Goater wrote: >>> A recent attempt to restrict the use of rfi to 64bit cpus in qemu >>> broke 32bit OpenBIOS when run under a 970. >>> >>> This is adding a dynamic check on the pvr to choose between rfi and >>> rfid. Only the 970 family is supported. >>> >>> Signed-off-by: Cédric Le Goater clg@kaod.org >>> --- >>> >>> Tested on qemu. >>> >>> arch/ppc/qemu/start.S | 25 +++++++++++++++++++++++-- >>> arch/ppc/start.S | 25 +++++++++++++++++++++++-- >>> 2 files changed, 46 insertions(+), 4 deletions(-) >>> >>> Index: openbios.git/arch/ppc/qemu/start.S >>> =================================================================== >>> --- openbios.git.orig/arch/ppc/qemu/start.S >>> +++ openbios.git/arch/ppc/qemu/start.S >>> @@ -27,6 +27,27 @@ >>> #ifdef CONFIG_PPC_64BITSUPPORT >>> +/* When running on ppc64, we cannot use rfi anymore. Let's try to >>> + * catch which cpu we are running on and act accordingly. This is >>> + * for 970s only. >> Do you think you could move the check into the cpu init function and use >> a global variable / live patching instead? I don't remember if we need >> to handle any faults before we reach that path. > So we get an ISI really early, when returning from setup_mmu(), which is > the first call in _entry. Ok, can we add the check there?
Bear in mind that the code for entry/context switching has been reworked pending commit whilst we switch the OpenBIOS repository over from SVN to git. The relevant commits are here: https://www.coreboot.org/pipermail/openbios/2016-May/009395.html.
So please consider OpenBIOS git master plus the patchset above to be the latest code.
OK. The first version applies fine. I pushed everything here :
https://github.com/legoater/openbios/commits/masterI am still looking at what Alex is asking for : a global variable doing live patching for rfi.
It's not both - it's either or :).
ah :) I need to grow my live patching skills.
So either you define a global variable that we can just read from to determine whether we do rfi or rfid
That is what I started doing and that was much bigger then v1.
or we live patch. Looking at the code, it's probably easiest to live patch even. Just call a function from setup_mmu() that checks PVR and if it's 64bit, loops through (0x0 .. 0x1000) in 32bit steps and checks if *p == INST_RFI. If so, replace with INST_RFID and flush the cache.
Indeed, the hunk below seems to do the trick :
@@ -524,6 +524,17 @@ setup_mmu(unsigned long ramsize) asm volatile("mtsrin %0,%1" :: "r" (sr_base + i), "r" (j)); }
- if (is_ppc64()) {
+#define RFI 0x4c000064 +#define RFID 0x4c000024
unsigned long addr;for (addr = 0x2000; addr < 0x3000; addr += 4) {unsigned long *ptr = (unsigned long *) addr;if (*ptr == RFI) *ptr = RFID;Could you please use "unsigned int" or "uint32_t" instead of unsigned long here? ... in case anybody every tries to compile this in 64-bit mode...
oh yes, this needs clean ups and more tests. I have your -prom-env jewel for that :)
Thanks,
C.