Sukadev Bhattiprolu <[email protected]> writes: > Paul Clarke [[email protected]] wrote: > --- > > From f9e9e8460206bc3fa7eaa741b9a2bde22870b9e0 Mon Sep 17 00:00:00 2001
I know it's been a while but I think it would still be good to get this in a shape that we can merge it. Comments inline ... > From: root <[email protected]> > Date: Thu, 4 Aug 2016 23:13:37 -0400 > Subject: [PATCH 2/2] powerpc/pseries: Dynamically grow RMA size > > When booting a very large system with a large initrd we run out of space > for the flattened device tree (FDT). To fix this we must increase the > space allocated for the RMA region. > > The RMA size is hard-coded in the 'ibm_architecture_vec[]' and increasing > the size there will apply to all systems, large and small, so we want to > increase the RMA region only when necessary. > > When we run out of room for the FDT, set a new OF property, 'ibm,new-rma-size' > to the new RMA size (512MB) and issue a client-architecture-support (CAS) > call to the firmware. This will initiate a system reboot. Upon reboot we > notice the new property and update the RMA size accordingly. > > Fix suggested by Michael Ellerman. > > Signed-off-by: Sukadev Bhattiprolu <[email protected]> > > diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c > index f612a99..d1aaeda 100644 > --- a/arch/powerpc/kernel/prom_init.c > +++ b/arch/powerpc/kernel/prom_init.c > @@ -87,6 +87,9 @@ > int of_workarounds; > #endif > > +#define IBM_NEW_RMA_SIZE_PROP "ibm,new-rma-size" > +#define IBM_NEW_RMA_SIZE_STR "512" The property name should really start with "linux,", as it's a Linux property, not used by firmware at all. And does it need to contain a value? Just its existence is a flag that we want to increase the RMA size. So it could just be called "linux,increase-rma-size". And we don't need a #define for the name, it's not going to change once the code is in, and a #define just obscures the actual name. > @@ -898,6 +910,42 @@ static void fixup_nr_cores(void) > ptcores[1] = (cores >> 16) & 0xff; > ptcores[2] = (cores >> 8) & 0xff; > ptcores[3] = cores & 0xff; > + fixup_nr_cores_done = true; That code has changed upstream, so that won't apply. But that's OK, I don't think we need to do it anyway. > +static void __init fixup_rma_size(void) > +{ > + int rc; > + u64 size; > + unsigned char *min_rmap; > + phandle optnode; > + char str[64]; > + > + optnode = call_prom("finddevice", 1, 1, ADDR("/options")); > + if (!PHANDLE_VALID(optnode)) > + prom_panic("Cannot find /options"); > + > + /* > + * If a prior boot specified a new RMA size, use that size in > + * ibm_architecture_vec[]. See also increase_rma_size(). > + */ > + size = 0ULL; > + memset(str, 0, sizeof(str)); > + rc = prom_getprop(optnode, IBM_NEW_RMA_SIZE_PROP, &str, sizeof(str)); > + if (rc <= 0) > + return; So this can just become something like: rc = prom_getprop(optnode, "linux,increase-rma-size", NULL, 0) if (rc == PROM_ERROR) return; val = be32_to_cpu(ibm_architecture_vec.vec2.min_rma); ibm_architecture_vec.vec2.min_rma = cpu_to_be32(val * 2); > @@ -946,6 +996,49 @@ static void __init prom_send_capabilities(void) > } > #endif /* __BIG_ENDIAN__ */ > } > + > +static void __init increase_rma_size(void) > +{ > + int rc, len; > + char str[64]; > + phandle optnode; > + > + optnode = call_prom("finddevice", 1, 1, ADDR("/options")); > + if (!PHANDLE_VALID(optnode)) > + prom_panic("Cannot find /options"); > + > + /* > + * If we already increased the RMA size, return. > + */ > + memset(str, 0, sizeof(str)); > + rc = prom_getprop(optnode, IBM_NEW_RMA_SIZE_PROP, &str, sizeof(str)); > + > + if (!strcmp(str, IBM_NEW_RMA_SIZE_STR)) { > + prom_printf("RMA size already at %.3s.\n", str); > + return; > + } > + /* > + * Otherwise, set the ibm,new-rma-size property and initiate a CAS > + * reboot so the RMA size can take effect. See also init_rma_size(). > + */ > + len = strlen(IBM_NEW_RMA_SIZE_STR) + 1; > + memcpy(str, IBM_NEW_RMA_SIZE_STR, len); > + > + prom_printf("Setting %s property to %s\n", IBM_NEW_RMA_SIZE_PROP, str); > + rc = prom_setprop(optnode, "/options", IBM_NEW_RMA_SIZE_PROP, str, len); We should check rc there shouldn't we? Again that code can be simpler if the property is just a flag. > + /* Force a reboot. Will work only if ibm,fw-override-cas==false */ > + prom_send_capabilities(); > + > + prom_printf("No CAS initiated reboot? Try setting ibm,fw-override-cas > to 'false' in Open Firmware\n"); I'm not sure if we want to be referring to ibm,fw-override-case. I don't thing it's a documented property (not in PAPR anyway), and it's certainly IBM PFW specific even if it is. I know for a fact that on KVM you won't get rebooted here, so I think if the CAS returns we should just reboot directly. cheers
