From f5f6cbb61610b7bf9d9d96db9c3979d62a424bab Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 27 Aug 2013 16:38:33 +1000 Subject: [PATCH 1/3] powerpc: Don't Oops when accessing /proc/powerpc/lparcfg without hypervisor /proc/powerpc/lparcfg is an ancient facility (though still actively used) which allows access to some informations relative to the partition when running underneath a PAPR compliant hypervisor. It makes no sense on non-pseries machines. However, currently, not only can it be created on these if the kernel has pseries support, but accessing it on such a machine will crash due to trying to do hypervisor calls. In fact, it should also not do HV calls on older pseries that didn't have an hypervisor either. Finally, it has the plumbing to be a module but is a "bool" Kconfig option. This fixes the whole lot by turning it into a machine_device_initcall that is only created on pseries, and adding the necessary hypervisor check before calling the H_GET_EM_PARMS hypercall CC: Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/lparcfg.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c index d92f3871e9cf..e2a0a162299b 100644 --- a/arch/powerpc/kernel/lparcfg.c +++ b/arch/powerpc/kernel/lparcfg.c @@ -35,7 +35,13 @@ #include #include #include +#include + +/* + * This isn't a module but we expose that to userspace + * via /proc so leave the definitions here + */ #define MODULE_VERS "1.9" #define MODULE_NAME "lparcfg" @@ -418,7 +424,8 @@ static void parse_em_data(struct seq_file *m) { unsigned long retbuf[PLPAR_HCALL_BUFSIZE]; - if (plpar_hcall(H_GET_EM_PARMS, retbuf) == H_SUCCESS) + if (firmware_has_feature(FW_FEATURE_LPAR) && + plpar_hcall(H_GET_EM_PARMS, retbuf) == H_SUCCESS) seq_printf(m, "power_mode_data=%016lx\n", retbuf[0]); } @@ -677,7 +684,6 @@ static int lparcfg_open(struct inode *inode, struct file *file) } static const struct file_operations lparcfg_fops = { - .owner = THIS_MODULE, .read = seq_read, .write = lparcfg_write, .open = lparcfg_open, @@ -699,14 +705,4 @@ static int __init lparcfg_init(void) } return 0; } - -static void __exit lparcfg_cleanup(void) -{ - remove_proc_subtree("powerpc/lparcfg", NULL); -} - -module_init(lparcfg_init); -module_exit(lparcfg_cleanup); -MODULE_DESCRIPTION("Interface for LPAR configuration data"); -MODULE_AUTHOR("Dave Engebretsen"); -MODULE_LICENSE("GPL"); +machine_device_initcall(pseries, lparcfg_init); From bdbc29c19b2633b1d9c52638fb732bcde7a2031a Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Tue, 27 Aug 2013 16:07:49 +1000 Subject: [PATCH 2/3] powerpc: Work around gcc miscompilation of __pa() on 64-bit On 64-bit, __pa(&static_var) gets miscompiled by recent versions of gcc as something like: addis 3,2,.LANCHOR1+4611686018427387904@toc@ha addi 3,3,.LANCHOR1+4611686018427387904@toc@l This ends up effectively ignoring the offset, since its bottom 32 bits are zero, and means that the result of __pa() still has 0xC in the top nibble. This happens with gcc 4.8.1, at least. To work around this, for 64-bit we make __pa() use an AND operator, and for symmetry, we make __va() use an OR operator. Using an AND operator rather than a subtraction ends up with slightly shorter code since it can be done with a single clrldi instruction, whereas it takes three instructions to form the constant (-PAGE_OFFSET) and add it on. (Note that MEMORY_START is always 0 on 64-bit.) CC: Signed-off-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/page.h | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index dbd9d3c991e8..9cf59816d3e9 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -979,6 +979,7 @@ config RELOCATABLE must live at a different physical address than the primary kernel. +# This value must have zeroes in the bottom 60 bits otherwise lots will break config PAGE_OFFSET hex default "0xc000000000000000" diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 988c812aab5b..b9f426212d3a 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -211,9 +211,19 @@ extern long long virt_phys_offset; #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET)) #define __pa(x) ((unsigned long)(x) - VIRT_PHYS_OFFSET) #else +#ifdef CONFIG_PPC64 +/* + * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET + * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit. + */ +#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET)) +#define __pa(x) ((unsigned long)(x) & 0x0fffffffffffffffUL) + +#else /* 32-bit, non book E */ #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START)) #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START) #endif +#endif /* * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI, From d220980b701d838560a70de691b53be007e99e78 Mon Sep 17 00:00:00 2001 From: Eugene Surovegin Date: Mon, 26 Aug 2013 11:53:32 -0700 Subject: [PATCH 3/3] powerpc/hvsi: Increase handshake timeout from 200ms to 400ms. This solves a problem observed in kexec'ed kernel where 200ms timeout is too short and bootconsole fails to initialize. Console did eventually become workable but much later into the boot process. Observed timeout was around 260ms, but I decided to make it a little bigger for more reliability. This has been tested on Power7 machine with Petitboot as a primary bootloader and PowerNV firmware. CC: Signed-off-by: Eugene Surovegin Signed-off-by: Benjamin Herrenschmidt --- drivers/tty/hvc/hvsi_lib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/hvc/hvsi_lib.c b/drivers/tty/hvc/hvsi_lib.c index 3396eb9d57a3..ac2767100df5 100644 --- a/drivers/tty/hvc/hvsi_lib.c +++ b/drivers/tty/hvc/hvsi_lib.c @@ -341,8 +341,8 @@ void hvsilib_establish(struct hvsi_priv *pv) pr_devel("HVSI@%x: ... waiting handshake\n", pv->termno); - /* Try for up to 200s */ - for (timeout = 0; timeout < 20; timeout++) { + /* Try for up to 400ms */ + for (timeout = 0; timeout < 40; timeout++) { if (pv->established) goto established; if (!hvsi_get_packet(pv))