From 83a092cf95f28696ddc36c8add0cf03ac034897f Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 12 May 2017 03:40:40 +1000 Subject: powerpc: Link warning for orphan sections Add --orphan-handling=warn to final link flags. This ensures we can handle all sections explicitly. This would have caught subtle breakage such as 7de3b27bac47da9de08409df1d69664acbb72197 at build-time. Also bring existing orphan sections into the fold: - .text.hot and .text.unlikely are compiler generated sections. - .sdata2, .dynsbss, .plt are used by PPC32 - We previously did not specify DWARF_DEBUG or STABS_DEBUG - DWARF_DEBUG did not include all DWARF sections that can be emitted - A number of sections are unused and can be discarded. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- include/asm-generic/vmlinux.lds.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'include') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 314a0b9219c6..9862afb3ae05 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -595,6 +595,7 @@ #define SBSS(sbss_align) \ . = ALIGN(sbss_align); \ .sbss : AT(ADDR(.sbss) - LOAD_OFFSET) { \ + *(.dynsbss) \ *(.sbss) \ *(.scommon) \ } @@ -641,11 +642,22 @@ .debug_str 0 : { *(.debug_str) } \ .debug_loc 0 : { *(.debug_loc) } \ .debug_macinfo 0 : { *(.debug_macinfo) } \ + .debug_pubtypes 0 : { *(.debug_pubtypes) } \ + /* DWARF 3 */ \ + .debug_ranges 0 : { *(.debug_ranges) } \ /* SGI/MIPS DWARF 2 extensions */ \ .debug_weaknames 0 : { *(.debug_weaknames) } \ .debug_funcnames 0 : { *(.debug_funcnames) } \ .debug_typenames 0 : { *(.debug_typenames) } \ .debug_varnames 0 : { *(.debug_varnames) } \ + /* GNU DWARF 2 extensions */ \ + .debug_gnu_pubnames 0 : { *(.debug_gnu_pubnames) } \ + .debug_gnu_pubtypes 0 : { *(.debug_gnu_pubtypes) } \ + /* DWARF 4 */ \ + .debug_types 0 : { *(.debug_types) } \ + /* DWARF 5 */ \ + .debug_macro 0 : { *(.debug_macro) } \ + .debug_addr 0 : { *(.debug_addr) } /* Stabs debugging sections. */ #define STABS_DEBUG \ -- cgit v1.2.3 From fd851a3cdc196bfc1d229b5f22369069af532bf8 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Mon, 29 May 2017 12:22:23 +1000 Subject: spin loop primitives for busy waiting Current busy-wait loops are implemented by repeatedly calling cpu_relax() to give an arch option for a low-latency option to improve power and/or SMT resource contention. This poses some difficulties for powerpc, which has SMT priority setting instructions (priorities determine how ifetch cycles are apportioned). powerpc's cpu_relax() is implemented by setting a low priority then setting normal priority. This has several problems: - Changing thread priority can have some execution cost and potential impact to other threads in the core. It's inefficient to execute them every time around a busy-wait loop. - Depending on implementation details, a `low ; medium` sequence may not have much if any affect. Some software with similar pattern actually inserts a lot of nops between, in order to cause a few fetch cycles with the low priority. - The busy-wait loop runs with regular priority. This might only be a few fetch cycles, but if there are several threads running such loops, they could cause a noticable impact on a non-idle thread. Implement spin_begin, spin_end primitives that can be used around busy wait loops, which default to no-ops. And spin_cpu_relax which defaults to cpu_relax. This will allow architectures to hook the entry and exit of busy-wait loops, and will allow powerpc to set low SMT priority at entry, and normal priority at exit. Suggested-by: Linus Torvalds Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- include/linux/processor.h | 70 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 include/linux/processor.h (limited to 'include') diff --git a/include/linux/processor.h b/include/linux/processor.h new file mode 100644 index 000000000000..da0c5e56ca02 --- /dev/null +++ b/include/linux/processor.h @@ -0,0 +1,70 @@ +/* Misc low level processor primitives */ +#ifndef _LINUX_PROCESSOR_H +#define _LINUX_PROCESSOR_H + +#include + +/* + * spin_begin is used before beginning a busy-wait loop, and must be paired + * with spin_end when the loop is exited. spin_cpu_relax must be called + * within the loop. + * + * The loop body should be as small and fast as possible, on the order of + * tens of instructions/cycles as a guide. It should and avoid calling + * cpu_relax, or any "spin" or sleep type of primitive including nested uses + * of these primitives. It should not lock or take any other resource. + * Violations of these guidelies will not cause a bug, but may cause sub + * optimal performance. + * + * These loops are optimized to be used where wait times are expected to be + * less than the cost of a context switch (and associated overhead). + * + * Detection of resource owner and decision to spin or sleep or guest-yield + * (e.g., spin lock holder vcpu preempted, or mutex owner not on CPU) can be + * tested within the loop body. + */ +#ifndef spin_begin +#define spin_begin() +#endif + +#ifndef spin_cpu_relax +#define spin_cpu_relax() cpu_relax() +#endif + +/* + * spin_cpu_yield may be called to yield (undirected) to the hypervisor if + * necessary. This should be used if the wait is expected to take longer + * than context switch overhead, but we can't sleep or do a directed yield. + */ +#ifndef spin_cpu_yield +#define spin_cpu_yield() cpu_relax_yield() +#endif + +#ifndef spin_end +#define spin_end() +#endif + +/* + * spin_until_cond can be used to wait for a condition to become true. It + * may be expected that the first iteration will true in the common case + * (no spinning), so that callers should not require a first "likely" test + * for the uncontended case before using this primitive. + * + * Usage and implementation guidelines are the same as for the spin_begin + * primitives, above. + */ +#ifndef spin_until_cond +#define spin_until_cond(cond) \ +do { \ + if (unlikely(!(cond))) { \ + spin_begin(); \ + do { \ + spin_cpu_relax(); \ + } while (!(cond)); \ + spin_end(); \ + } \ +} while (0) + +#endif + +#endif /* _LINUX_PROCESSOR_H */ -- cgit v1.2.3 From 3ced8d73006321bd2a0412fa0ff4b065a02e7514 Mon Sep 17 00:00:00 2001 From: Christophe Lombard Date: Thu, 22 Jun 2017 15:07:27 +0200 Subject: cxl: Export library to support IBM XSL This patch exports a in-kernel 'library' API which can be called by other drivers to help interacting with an IBM XSL on a POWER9 system. The XSL (Translation Service Layer) is a stripped down version of the PSL (Power Service Layer) used in some cards such as the Mellanox CX5. Like the PSL, it implements the CAIA architecture, but has a number of differences, mostly in it's implementation dependent registers. The XSL also uses a special DMA cxl mode, which uses a slightly different init sequence for the CAPP and PHB. Signed-off-by: Andrew Donnellan Signed-off-by: Christophe Lombard Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman --- include/misc/cxllib.h | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 include/misc/cxllib.h (limited to 'include') diff --git a/include/misc/cxllib.h b/include/misc/cxllib.h new file mode 100644 index 000000000000..e5aa29f019a6 --- /dev/null +++ b/include/misc/cxllib.h @@ -0,0 +1,133 @@ +/* + * Copyright 2017 IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _MISC_CXLLIB_H +#define _MISC_CXLLIB_H + +#include +#include + +/* + * cxl driver exports a in-kernel 'library' API which can be called by + * other drivers to help interacting with an IBM XSL. + */ + +/* + * tells whether capi is supported on the PCIe slot where the + * device is seated + * + * Input: + * dev: device whose slot needs to be checked + * flags: 0 for the time being + */ +bool cxllib_slot_is_supported(struct pci_dev *dev, unsigned long flags); + + +/* + * Returns the configuration parameters to be used by the XSL or device + * + * Input: + * dev: device, used to find PHB + * Output: + * struct cxllib_xsl_config: + * version + * capi BAR address, i.e. 0x2000000000000-0x2FFFFFFFFFFFF + * capi BAR size + * data send control (XSL_DSNCTL) + * dummy read address (XSL_DRA) + */ +#define CXL_XSL_CONFIG_VERSION1 1 +struct cxllib_xsl_config { + u32 version; /* format version for register encoding */ + u32 log_bar_size;/* log size of the capi_window */ + u64 bar_addr; /* address of the start of capi window */ + u64 dsnctl; /* matches definition of XSL_DSNCTL */ + u64 dra; /* real address that can be used for dummy read */ +}; + +int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg); + + +/* + * Activate capi for the pci host bridge associated with the device. + * Can be extended to deactivate once we know how to do it. + * Device must be ready to accept messages from the CAPP unit and + * respond accordingly (TLB invalidates, ...) + * + * PHB is switched to capi mode through calls to skiboot. + * CAPP snooping is activated + * + * Input: + * dev: device whose PHB should switch mode + * mode: mode to switch to i.e. CAPI or PCI + * flags: options related to the mode + */ +enum cxllib_mode { + CXL_MODE_CXL, + CXL_MODE_PCI, +}; + +#define CXL_MODE_NO_DMA 0 +#define CXL_MODE_DMA_TVT0 1 +#define CXL_MODE_DMA_TVT1 2 + +int cxllib_switch_phb_mode(struct pci_dev *dev, enum cxllib_mode mode, + unsigned long flags); + + +/* + * Set the device for capi DMA. + * Define its dma_ops and dma offset so that allocations will be using TVT#1 + * + * Input: + * dev: device to set + * flags: options. CXL_MODE_DMA_TVT1 should be used + */ +int cxllib_set_device_dma(struct pci_dev *dev, unsigned long flags); + + +/* + * Get the Process Element structure for the given thread + * + * Input: + * task: task_struct for the context of the translation + * translation_mode: whether addresses should be translated + * Output: + * attr: attributes to fill up the Process Element structure from CAIA + */ +struct cxllib_pe_attributes { + u64 sr; + u32 lpid; + u32 tid; + u32 pid; +}; +#define CXL_TRANSLATED_MODE 0 +#define CXL_REAL_MODE 1 + +int cxllib_get_PE_attributes(struct task_struct *task, + unsigned long translation_mode, struct cxllib_pe_attributes *attr); + + +/* + * Handle memory fault. + * Fault in all the pages of the specified buffer for the permissions + * provided in ‘flags’ + * + * Shouldn't be called from interrupt context + * + * Input: + * mm: struct mm for the thread faulting the pages + * addr: base address of the buffer to page in + * size: size of the buffer to page in + * flags: permission requested (DSISR_ISSTORE...) + */ +int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags); + + +#endif /* _MISC_CXLLIB_H */ -- cgit v1.2.3