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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 20:09:55 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 20:09:55 -0500
commit9d3cae26acb471d5954cfdc25d1438b32060babe (patch)
tree77e93b6fb207438f7f1f30a201cc86bc5b0ec82b /Documentation
parentdf24eef3e794afbac69a377d1d2e2e3f5869f67a (diff)
parent8520e443aa56cc157b015205ea53e7b9fc831291 (diff)
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull powerpc updates from Benjamin Herrenschmidt: "So from the depth of frozen Minnesota, here's the powerpc pull request for 3.9. It has a few interesting highlights, in addition to the usual bunch of bug fixes, minor updates, embedded device tree updates and new boards: - Hand tuned asm implementation of SHA1 (by Paulus & Michael Ellerman) - Support for Doorbell interrupts on Power8 (kind of fast thread-thread IPIs) by Ian Munsie - Long overdue cleanup of the way we handle relocation of our open firmware trampoline (prom_init.c) on 64-bit by Anton Blanchard - Support for saving/restoring & context switching the PPR (Processor Priority Register) on server processors that support it. This allows the kernel to preserve thread priorities established by userspace. By Haren Myneni. - DAWR (new watchpoint facility) support on Power8 by Michael Neuling - Ability to change the DSCR (Data Stream Control Register) which controls cache prefetching on a running process via ptrace by Alexey Kardashevskiy - Support for context switching the TAR register on Power8 (new branch target register meant to be used by some new specific userspace perf event interrupt facility which is yet to be enabled) by Ian Munsie. - Improve preservation of the CFAR register (which captures the origin of a branch) on various exception conditions by Paulus. - Move the Bestcomm DMA driver from arch powerpc to drivers/dma where it belongs by Philippe De Muyter - Support for Transactional Memory on Power8 by Michael Neuling (based on original work by Matt Evans). For those curious about the feature, the patch contains a pretty good description." (See commit db8ff907027b: "powerpc: Documentation for transactional memory on powerpc" for the mentioned description added to the file Documentation/powerpc/transactional_memory.txt) * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (140 commits) powerpc/kexec: Disable hard IRQ before kexec powerpc/85xx: l2sram - Add compatible string for BSC9131 platform powerpc/85xx: bsc9131 - Correct typo in SDHC device node powerpc/e500/qemu-e500: enable coreint powerpc/mpic: allow coreint to be determined by MPIC version powerpc/fsl_pci: Store the pci ctlr device ptr in the pci ctlr struct powerpc/85xx: Board support for ppa8548 powerpc/fsl: remove extraneous DIU platform functions arch/powerpc/platforms/85xx/p1022_ds.c: adjust duplicate test powerpc: Documentation for transactional memory on powerpc powerpc: Add transactional memory to pseries and ppc64 defconfigs powerpc: Add config option for transactional memory powerpc: Add transactional memory to POWER8 cpu features powerpc: Add new transactional memory state to the signal context powerpc: Hook in new transactional memory code powerpc: Routines for FP/VSX/VMX unavailable during a transaction powerpc: Add transactional memory unavaliable execption handler powerpc: Add reclaim and recheckpoint functions for context switching transactional memory processes powerpc: Add FP/VSX and VMX register load functions for transactional memory powerpc: Add helper functions for transactional memory context switching ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/crypto/fsl-sec4.txt12
-rw-r--r--Documentation/devicetree/bindings/powerpc/fsl/guts.txt13
-rw-r--r--Documentation/devicetree/bindings/powerpc/fsl/pamu.txt140
-rw-r--r--Documentation/powerpc/cpu_features.txt10
-rw-r--r--Documentation/powerpc/transactional_memory.txt175
5 files changed, 341 insertions, 9 deletions
diff --git a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
index fc9ce6f1688c..6d21c0288e9e 100644
--- a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
+++ b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
@@ -54,8 +54,13 @@ PROPERTIES
54 - compatible 54 - compatible
55 Usage: required 55 Usage: required
56 Value type: <string> 56 Value type: <string>
57 Definition: Must include "fsl,sec-v4.0". Also includes SEC 57 Definition: Must include "fsl,sec-v4.0"
58 ERA versions (optional) with which the device is compatible. 58
59 - fsl,sec-era
60 Usage: optional
61 Value type: <u32>
62 Definition: A standard property. Define the 'ERA' of the SEC
63 device.
59 64
60 - #address-cells 65 - #address-cells
61 Usage: required 66 Usage: required
@@ -107,7 +112,8 @@ PROPERTIES
107 112
108EXAMPLE 113EXAMPLE
109 crypto@300000 { 114 crypto@300000 {
110 compatible = "fsl,sec-v4.0", "fsl,sec-era-v2.0"; 115 compatible = "fsl,sec-v4.0";
116 fsl,sec-era = <0x2>;
111 #address-cells = <1>; 117 #address-cells = <1>;
112 #size-cells = <1>; 118 #size-cells = <1>;
113 reg = <0x300000 0x10000>; 119 reg = <0x300000 0x10000>;
diff --git a/Documentation/devicetree/bindings/powerpc/fsl/guts.txt b/Documentation/devicetree/bindings/powerpc/fsl/guts.txt
index 9e7a2417dac5..7f150b5012cc 100644
--- a/Documentation/devicetree/bindings/powerpc/fsl/guts.txt
+++ b/Documentation/devicetree/bindings/powerpc/fsl/guts.txt
@@ -17,9 +17,20 @@ Recommended properties:
17 contains a functioning "reset control register" (i.e. the board 17 contains a functioning "reset control register" (i.e. the board
18 is wired to reset upon setting the HRESET_REQ bit in this register). 18 is wired to reset upon setting the HRESET_REQ bit in this register).
19 19
20Example: 20 - fsl,liodn-bits : Indicates the number of defined bits in the LIODN
21 registers, for those SOCs that have a PAMU device.
22
23Examples:
21 global-utilities@e0000 { /* global utilities block */ 24 global-utilities@e0000 { /* global utilities block */
22 compatible = "fsl,mpc8548-guts"; 25 compatible = "fsl,mpc8548-guts";
23 reg = <e0000 1000>; 26 reg = <e0000 1000>;
24 fsl,has-rstcr; 27 fsl,has-rstcr;
25 }; 28 };
29
30 guts: global-utilities@e0000 {
31 compatible = "fsl,qoriq-device-config-1.0";
32 reg = <0xe0000 0xe00>;
33 fsl,has-rstcr;
34 #sleep-cells = <1>;
35 fsl,liodn-bits = <12>;
36 };
diff --git a/Documentation/devicetree/bindings/powerpc/fsl/pamu.txt b/Documentation/devicetree/bindings/powerpc/fsl/pamu.txt
new file mode 100644
index 000000000000..1f5e329f756c
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/fsl/pamu.txt
@@ -0,0 +1,140 @@
1Freescale Peripheral Management Access Unit (PAMU) Device Tree Binding
2
3DESCRIPTION
4
5The PAMU is an I/O MMU that provides device-to-memory access control and
6address translation capabilities.
7
8Required properties:
9
10- compatible : <string>
11 First entry is a version-specific string, such as
12 "fsl,pamu-v1.0". The second is "fsl,pamu".
13- ranges : <prop-encoded-array>
14 A standard property. Utilized to describe the memory mapped
15 I/O space utilized by the controller. The size should
16 be set to the total size of the register space of all
17 physically present PAMU controllers. For example, for
18 PAMU v1.0, on an SOC that has five PAMU devices, the size
19 is 0x5000.
20- interrupts : <prop-encoded-array>
21 Interrupt mappings. The first tuple is the normal PAMU
22 interrupt, used for reporting access violations. The second
23 is for PAMU hardware errors, such as PAMU operation errors
24 and ECC errors.
25- #address-cells: <u32>
26 A standard property.
27- #size-cells : <u32>
28 A standard property.
29
30Optional properties:
31- reg : <prop-encoded-array>
32 A standard property. It represents the CCSR registers of
33 all child PAMUs combined. Include it to provide support
34 for legacy drivers.
35- interrupt-parent : <phandle>
36 Phandle to interrupt controller
37
38Child nodes:
39
40Each child node represents one PAMU controller. Each SOC device that is
41connected to a specific PAMU device should have a "fsl,pamu-phandle" property
42that links to the corresponding specific child PAMU controller.
43
44- reg : <prop-encoded-array>
45 A standard property. Specifies the physical address and
46 length (relative to the parent 'ranges' property) of this
47 PAMU controller's configuration registers. The size should
48 be set to the size of this PAMU controllers's register space.
49 For PAMU v1.0, this size is 0x1000.
50- fsl,primary-cache-geometry
51 : <prop-encoded-array>
52 Two cells that specify the geometry of the primary PAMU
53 cache. The first is the number of cache lines, and the
54 second is the number of "ways". For direct-mapped caches,
55 specify a value of 1.
56- fsl,secondary-cache-geometry
57 : <prop-encoded-array>
58 Two cells that specify the geometry of the secondary PAMU
59 cache. The first is the number of cache lines, and the
60 second is the number of "ways". For direct-mapped caches,
61 specify a value of 1.
62
63Device nodes:
64
65Devices that have LIODNs need to specify links to the parent PAMU controller
66(the actual PAMU controller that this device is connected to) and a pointer to
67the LIODN register, if applicable.
68
69- fsl,iommu-parent
70 : <phandle>
71 Phandle to the single, specific PAMU controller node to which
72 this device is connect. The PAMU topology is represented in
73 the device tree to assist code that dynamically determines the
74 best LIODN values to minimize PAMU cache thrashing.
75
76- fsl,liodn-reg : <prop-encoded-array>
77 Two cells that specify the location of the LIODN register
78 for this device. Required for devices that have a single
79 LIODN. The first cell is a phandle to a node that contains
80 the registers where the LIODN is to be set. The second is
81 the offset from the first "reg" resource of the node where
82 the specific LIODN register is located.
83
84
85Example:
86
87 iommu@20000 {
88 compatible = "fsl,pamu-v1.0", "fsl,pamu";
89 reg = <0x20000 0x5000>;
90 ranges = <0 0x20000 0x5000>;
91 #address-cells = <1>;
92 #size-cells = <1>;
93 interrupts = <
94 24 2 0 0
95 16 2 1 30>;
96
97 pamu0: pamu@0 {
98 reg = <0 0x1000>;
99 fsl,primary-cache-geometry = <32 1>;
100 fsl,secondary-cache-geometry = <128 2>;
101 };
102
103 pamu1: pamu@1000 {
104 reg = <0x1000 0x1000>;
105 fsl,primary-cache-geometry = <32 1>;
106 fsl,secondary-cache-geometry = <128 2>;
107 };
108
109 pamu2: pamu@2000 {
110 reg = <0x2000 0x1000>;
111 fsl,primary-cache-geometry = <32 1>;
112 fsl,secondary-cache-geometry = <128 2>;
113 };
114
115 pamu3: pamu@3000 {
116 reg = <0x3000 0x1000>;
117 fsl,primary-cache-geometry = <32 1>;
118 fsl,secondary-cache-geometry = <128 2>;
119 };
120
121 pamu4: pamu@4000 {
122 reg = <0x4000 0x1000>;
123 fsl,primary-cache-geometry = <32 1>;
124 fsl,secondary-cache-geometry = <128 2>;
125 };
126 };
127
128 guts: global-utilities@e0000 {
129 compatible = "fsl,qoriq-device-config-1.0";
130 reg = <0xe0000 0xe00>;
131 fsl,has-rstcr;
132 #sleep-cells = <1>;
133 fsl,liodn-bits = <12>;
134 };
135
136/include/ "qoriq-dma-0.dtsi"
137 dma@100300 {
138 fsl,iommu-parent = <&pamu0>;
139 fsl,liodn-reg = <&guts 0x584>; /* DMA2LIODNR */
140 };
diff --git a/Documentation/powerpc/cpu_features.txt b/Documentation/powerpc/cpu_features.txt
index ffa4183fdb8b..ae09df8722c8 100644
--- a/Documentation/powerpc/cpu_features.txt
+++ b/Documentation/powerpc/cpu_features.txt
@@ -11,10 +11,10 @@ split instruction and data caches, and if the CPU supports the DOZE and NAP
11sleep modes. 11sleep modes.
12 12
13Detection of the feature set is simple. A list of processors can be found in 13Detection of the feature set is simple. A list of processors can be found in
14arch/ppc/kernel/cputable.c. The PVR register is masked and compared with each 14arch/powerpc/kernel/cputable.c. The PVR register is masked and compared with
15value in the list. If a match is found, the cpu_features of cur_cpu_spec is 15each value in the list. If a match is found, the cpu_features of cur_cpu_spec
16assigned to the feature bitmask for this processor and a __setup_cpu function 16is assigned to the feature bitmask for this processor and a __setup_cpu
17is called. 17function is called.
18 18
19C code may test 'cur_cpu_spec[smp_processor_id()]->cpu_features' for a 19C code may test 'cur_cpu_spec[smp_processor_id()]->cpu_features' for a
20particular feature bit. This is done in quite a few places, for example 20particular feature bit. This is done in quite a few places, for example
@@ -51,6 +51,6 @@ should be used in the majority of cases.
51 51
52The END_FTR_SECTION macros are implemented by storing information about this 52The END_FTR_SECTION macros are implemented by storing information about this
53code in the '__ftr_fixup' ELF section. When do_cpu_ftr_fixups 53code in the '__ftr_fixup' ELF section. When do_cpu_ftr_fixups
54(arch/ppc/kernel/misc.S) is invoked, it will iterate over the records in 54(arch/powerpc/kernel/misc.S) is invoked, it will iterate over the records in
55__ftr_fixup, and if the required feature is not present it will loop writing 55__ftr_fixup, and if the required feature is not present it will loop writing
56nop's from each BEGIN_FTR_SECTION to END_FTR_SECTION. 56nop's from each BEGIN_FTR_SECTION to END_FTR_SECTION.
diff --git a/Documentation/powerpc/transactional_memory.txt b/Documentation/powerpc/transactional_memory.txt
new file mode 100644
index 000000000000..c907be41d60f
--- /dev/null
+++ b/Documentation/powerpc/transactional_memory.txt
@@ -0,0 +1,175 @@
1Transactional Memory support
2============================
3
4POWER kernel support for this feature is currently limited to supporting
5its use by user programs. It is not currently used by the kernel itself.
6
7This file aims to sum up how it is supported by Linux and what behaviour you
8can expect from your user programs.
9
10
11Basic overview
12==============
13
14Hardware Transactional Memory is supported on POWER8 processors, and is a
15feature that enables a different form of atomic memory access. Several new
16instructions are presented to delimit transactions; transactions are
17guaranteed to either complete atomically or roll back and undo any partial
18changes.
19
20A simple transaction looks like this:
21
22begin_move_money:
23 tbegin
24 beq abort_handler
25
26 ld r4, SAVINGS_ACCT(r3)
27 ld r5, CURRENT_ACCT(r3)
28 subi r5, r5, 1
29 addi r4, r4, 1
30 std r4, SAVINGS_ACCT(r3)
31 std r5, CURRENT_ACCT(r3)
32
33 tend
34
35 b continue
36
37abort_handler:
38 ... test for odd failures ...
39
40 /* Retry the transaction if it failed because it conflicted with
41 * someone else: */
42 b begin_move_money
43
44
45The 'tbegin' instruction denotes the start point, and 'tend' the end point.
46Between these points the processor is in 'Transactional' state; any memory
47references will complete in one go if there are no conflicts with other
48transactional or non-transactional accesses within the system. In this
49example, the transaction completes as though it were normal straight-line code
50IF no other processor has touched SAVINGS_ACCT(r3) or CURRENT_ACCT(r3); an
51atomic move of money from the current account to the savings account has been
52performed. Even though the normal ld/std instructions are used (note no
53lwarx/stwcx), either *both* SAVINGS_ACCT(r3) and CURRENT_ACCT(r3) will be
54updated, or neither will be updated.
55
56If, in the meantime, there is a conflict with the locations accessed by the
57transaction, the transaction will be aborted by the CPU. Register and memory
58state will roll back to that at the 'tbegin', and control will continue from
59'tbegin+4'. The branch to abort_handler will be taken this second time; the
60abort handler can check the cause of the failure, and retry.
61
62Checkpointed registers include all GPRs, FPRs, VRs/VSRs, LR, CCR/CR, CTR, FPCSR
63and a few other status/flag regs; see the ISA for details.
64
65Causes of transaction aborts
66============================
67
68- Conflicts with cache lines used by other processors
69- Signals
70- Context switches
71- See the ISA for full documentation of everything that will abort transactions.
72
73
74Syscalls
75========
76
77Performing syscalls from within transaction is not recommended, and can lead
78to unpredictable results.
79
80Syscalls do not by design abort transactions, but beware: The kernel code will
81not be running in transactional state. The effect of syscalls will always
82remain visible, but depending on the call they may abort your transaction as a
83side-effect, read soon-to-be-aborted transactional data that should not remain
84invisible, etc. If you constantly retry a transaction that constantly aborts
85itself by calling a syscall, you'll have a livelock & make no progress.
86
87Simple syscalls (e.g. sigprocmask()) "could" be OK. Even things like write()
88from, say, printf() should be OK as long as the kernel does not access any
89memory that was accessed transactionally.
90
91Consider any syscalls that happen to work as debug-only -- not recommended for
92production use. Best to queue them up till after the transaction is over.
93
94
95Signals
96=======
97
98Delivery of signals (both sync and async) during transactions provides a second
99thread state (ucontext/mcontext) to represent the second transactional register
100state. Signal delivery 'treclaim's to capture both register states, so signals
101abort transactions. The usual ucontext_t passed to the signal handler
102represents the checkpointed/original register state; the signal appears to have
103arisen at 'tbegin+4'.
104
105If the sighandler ucontext has uc_link set, a second ucontext has been
106delivered. For future compatibility the MSR.TS field should be checked to
107determine the transactional state -- if so, the second ucontext in uc->uc_link
108represents the active transactional registers at the point of the signal.
109
110For 64-bit processes, uc->uc_mcontext.regs->msr is a full 64-bit MSR and its TS
111field shows the transactional mode.
112
113For 32-bit processes, the mcontext's MSR register is only 32 bits; the top 32
114bits are stored in the MSR of the second ucontext, i.e. in
115uc->uc_link->uc_mcontext.regs->msr. The top word contains the transactional
116state TS.
117
118However, basic signal handlers don't need to be aware of transactions
119and simply returning from the handler will deal with things correctly:
120
121Transaction-aware signal handlers can read the transactional register state
122from the second ucontext. This will be necessary for crash handlers to
123determine, for example, the address of the instruction causing the SIGSEGV.
124
125Example signal handler:
126
127 void crash_handler(int sig, siginfo_t *si, void *uc)
128 {
129 ucontext_t *ucp = uc;
130 ucontext_t *transactional_ucp = ucp->uc_link;
131
132 if (ucp_link) {
133 u64 msr = ucp->uc_mcontext.regs->msr;
134 /* May have transactional ucontext! */
135#ifndef __powerpc64__
136 msr |= ((u64)transactional_ucp->uc_mcontext.regs->msr) << 32;
137#endif
138 if (MSR_TM_ACTIVE(msr)) {
139 /* Yes, we crashed during a transaction. Oops. */
140 fprintf(stderr, "Transaction to be restarted at 0x%llx, but "
141 "crashy instruction was at 0x%llx\n",
142 ucp->uc_mcontext.regs->nip,
143 transactional_ucp->uc_mcontext.regs->nip);
144 }
145 }
146
147 fix_the_problem(ucp->dar);
148 }
149
150
151Failure cause codes used by kernel
152==================================
153
154These are defined in <asm/reg.h>, and distinguish different reasons why the
155kernel aborted a transaction:
156
157 TM_CAUSE_RESCHED Thread was rescheduled.
158 TM_CAUSE_FAC_UNAV FP/VEC/VSX unavailable trap.
159 TM_CAUSE_SYSCALL Currently unused; future syscalls that must abort
160 transactions for consistency will use this.
161 TM_CAUSE_SIGNAL Signal delivered.
162 TM_CAUSE_MISC Currently unused.
163
164These can be checked by the user program's abort handler as TEXASR[0:7].
165
166
167GDB
168===
169
170GDB and ptrace are not currently TM-aware. If one stops during a transaction,
171it looks like the transaction has just started (the checkpointed state is
172presented). The transaction cannot then be continued and will take the failure
173handler route. Furthermore, the transactional 2nd register state will be
174inaccessible. GDB can currently be used on programs using TM, but not sensibly
175in parts within transactions.