Automatic merge of 'next-test' into merge-test (2024-05-03 00:08)

Documentation/ABI/testing/sysfs-kernel-fadump

@@ -38,3 +38,14 @@ Contact:	[email protected]
 Description:	read only
 		Provide information about the amount of memory reserved by
 		FADump to save the crash dump in bytes.
+
+What:		/sys/kernel/fadump/hotplug_ready
+Date:		Apr 2024
+Contact:	[email protected]
+Description:	read only
+		Kdump udev rule re-registers fadump on memory add/remove events,
+		primarily to update the elfcorehdr. This sysfs indicates the
+		kdump udev rule that fadump re-registration is not required on
+		memory add/remove events because elfcorehdr is now prepared in
+		the second/fadump kernel.
+User:		kexec-tools

Documentation/arch/powerpc/dexcr.rst

@@ -36,8 +36,145 @@ state for a process.
 Configuration
 =============
 
-The DEXCR is currently unconfigurable. All threads are run with the
-NPHIE aspect enabled.
+prctl
+-----
+
+A process can control its own userspace DEXCR value using the
+``PR_PPC_GET_DEXCR`` and ``PR_PPC_SET_DEXCR`` pair of
+:manpage:`prctl(2)` commands. These calls have the form::
+
+    prctl(PR_PPC_GET_DEXCR, unsigned long which, 0, 0, 0);
+    prctl(PR_PPC_SET_DEXCR, unsigned long which, unsigned long ctrl, 0, 0);
+
+The possible 'which' and 'ctrl' values are as follows. Note there is no relation
+between the 'which' value and the DEXCR aspect's index.
+
+.. flat-table::
+   :header-rows: 1
+   :widths: 2 7 1
+
+   * - ``prctl()`` which
+     - Aspect name
+     - Aspect index
+
+   * - ``PR_PPC_DEXCR_SBHE``
+     - Speculative Branch Hint Enable (SBHE)
+     - 0
+
+   * - ``PR_PPC_DEXCR_IBRTPD``
+     - Indirect Branch Recurrent Target Prediction Disable (IBRTPD)
+     - 3
+
+   * - ``PR_PPC_DEXCR_SRAPD``
+     - Subroutine Return Address Prediction Disable (SRAPD)
+     - 4
+
+   * - ``PR_PPC_DEXCR_NPHIE``
+     - Non-Privileged Hash Instruction Enable (NPHIE)
+     - 5
+
+.. flat-table::
+   :header-rows: 1
+   :widths: 2 8
+
+   * - ``prctl()`` ctrl
+     - Meaning
+
+   * - ``PR_PPC_DEXCR_CTRL_EDITABLE``
+     - This aspect can be configured with PR_PPC_SET_DEXCR (get only)
+
+   * - ``PR_PPC_DEXCR_CTRL_SET``
+     - This aspect is set / set this aspect
+
+   * - ``PR_PPC_DEXCR_CTRL_CLEAR``
+     - This aspect is clear / clear this aspect
+
+   * - ``PR_PPC_DEXCR_CTRL_SET_ONEXEC``
+     - This aspect will be set after exec / set this aspect after exec
+
+   * - ``PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC``
+     - This aspect will be clear after exec / clear this aspect after exec
+
+Note that
+
+* which is a plain value, not a bitmask. Aspects must be worked with individually.
+
+* ctrl is a bitmask. ``PR_PPC_GET_DEXCR`` returns both the current and onexec
+  configuration. For example, ``PR_PPC_GET_DEXCR`` may return
+  ``PR_PPC_DEXCR_CTRL_EDITABLE | PR_PPC_DEXCR_CTRL_SET |
+  PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC``. This would indicate the aspect is currently
+  set, it will be cleared when you run exec, and you can change this with the
+  ``PR_PPC_SET_DEXCR`` prctl.
+
+* The set/clear terminology refers to setting/clearing the bit in the DEXCR.
+  For example::
+
+      prctl(PR_PPC_SET_DEXCR, PR_PPC_DEXCR_IBRTPD, PR_PPC_DEXCR_CTRL_SET, 0, 0);
+
+  will set the IBRTPD aspect bit in the DEXCR, causing indirect branch prediction
+  to be disabled.
+
+* The status returned by ``PR_PPC_GET_DEXCR`` represents what value the process
+  would like applied. It does not include any alternative overrides, such as if
+  the hypervisor is enforcing the aspect be set. To see the true DEXCR state
+  software should read the appropriate SPRs directly.
+
+* The aspect state when starting a process is copied from the parent's state on
+  :manpage:`fork(2)`. The state is reset to a fixed value on
+  :manpage:`execve(2)`. The PR_PPC_SET_DEXCR prctl() can control both of these
+  values.
+
+* The ``*_ONEXEC`` controls do not change the current process's DEXCR.
+
+Use ``PR_PPC_SET_DEXCR`` with one of ``PR_PPC_DEXCR_CTRL_SET`` or
+``PR_PPC_DEXCR_CTRL_CLEAR`` to edit a given aspect.
+
+Common error codes for both getting and setting the DEXCR are as follows:
+
+.. flat-table::
+   :header-rows: 1
+   :widths: 2 8
+
+   * - Error
+     - Meaning
+
+   * - ``EINVAL``
+     - The DEXCR is not supported by the kernel.
+
+   * - ``ENODEV``
+     - The aspect is not recognised by the kernel or not supported by the
+       hardware.
+
+``PR_PPC_SET_DEXCR`` may also report the following error codes:
+
+.. flat-table::
+   :header-rows: 1
+   :widths: 2 8
+
+   * - Error
+     - Meaning
+
+   * - ``EINVAL``
+     - The ctrl value contains unrecognised flags.
+
+   * - ``EINVAL``
+     - The ctrl value contains mutually conflicting flags (e.g.,
+       ``PR_PPC_DEXCR_CTRL_SET | PR_PPC_DEXCR_CTRL_CLEAR``)
+
+   * - ``EPERM``
+     - This aspect cannot be modified with prctl() (check for the
+       PR_PPC_DEXCR_CTRL_EDITABLE flag with PR_PPC_GET_DEXCR).
+
+   * - ``EPERM``
+     - The process does not have sufficient privilege to perform the operation.
+       For example, clearing NPHIE on exec is a privileged operation (a process
+       can still clear its own NPHIE aspect without privileges).
+
+This interface allows a process to control its own DEXCR aspects, and also set
+the initial DEXCR value for any children in its process tree (up to the next
+child to use an ``*_ONEXEC`` control). This allows fine-grained control over the
+default value of the DEXCR, for example allowing containers to run with different
+default values.
 
 
 coredump and ptrace

Documentation/arch/powerpc/firmware-assisted-dump.rst

@@ -134,12 +134,12 @@ that are run. If there is dump data, then the
 memory is held.
 
 If there is no waiting dump data, then only the memory required to
-hold CPU state, HPTE region, boot memory dump, FADump header and
-elfcore header, is usually reserved at an offset greater than boot
-memory size (see Fig. 1). This area is *not* released: this region
-will be kept permanently reserved, so that it can act as a receptacle
-for a copy of the boot memory content in addition to CPU state and
-HPTE region, in the case a crash does occur.
+hold CPU state, HPTE region, boot memory dump, and FADump header is
+usually reserved at an offset greater than boot memory size (see Fig. 1).
+This area is *not* released: this region will be kept permanently
+reserved, so that it can act as a receptacle for a copy of the boot
+memory content in addition to CPU state and HPTE region, in the case
+a crash does occur.
 
 Since this reserved memory area is used only after the system crash,
 there is no point in blocking this significant chunk of memory from
@@ -153,22 +153,22 @@ that were present in CMA region::
 
   o Memory Reservation during first kernel
 
-  Low memory                                                 Top of memory
-  0    boot memory size   |<--- Reserved dump area --->|       |
-  |           |           |    Permanent Reservation   |       |
-  V           V           |                            |       V
-  +-----------+-----/ /---+---+----+-------+-----+-----+----+--+
-  |           |           |///|////|  DUMP | HDR | ELF |////|  |
-  +-----------+-----/ /---+---+----+-------+-----+-----+----+--+
-        |                   ^    ^     ^      ^           ^
-        |                   |    |     |      |           |
-        \                  CPU  HPTE   /      |           |
-         ------------------------------       |           |
-      Boot memory content gets transferred    |           |
-      to reserved area by firmware at the     |           |
-      time of crash.                          |           |
-                                          FADump Header   |
-                                           (meta area)    |
+  Low memory                                                  Top of memory
+  0    boot memory size   |<------ Reserved dump area ----->|     |
+  |           |           |      Permanent Reservation      |     |
+  V           V           |                                 |     V
+  +-----------+-----/ /---+---+----+-----------+-------+----+-----+
+  |           |           |///|////|    DUMP   |  HDR  |////|     |
+  +-----------+-----/ /---+---+----+-----------+-------+----+-----+
+        |                   ^    ^       ^         ^      ^
+        |                   |    |       |         |      |
+        \                  CPU  HPTE     /         |      |
+         --------------------------------          |      |
+      Boot memory content gets transferred         |      |
+      to reserved area by firmware at the          |      |
+      time of crash.                               |      |
+                                           FADump Header  |
+                                            (meta area)   |
                                                           |
                                                           |
                       Metadata: This area holds a metadata structure whose
@@ -186,20 +186,33 @@ that were present in CMA region::
   0      boot memory size                                      |
   |           |<------------ Crash preserved area ------------>|
   V           V           |<--- Reserved dump area --->|       |
-  +-----------+-----/ /---+---+----+-------+-----+-----+----+--+
-  |           |           |///|////|  DUMP | HDR | ELF |////|  |
-  +-----------+-----/ /---+---+----+-------+-----+-----+----+--+
-        |                                           |
-        V                                           V
-   Used by second                             /proc/vmcore
-   kernel to boot
+  +----+---+--+-----/ /---+---+----+-------+-----+-----+-------+
+  |    |ELF|  |           |///|////|  DUMP | HDR |/////|       |
+  +----+---+--+-----/ /---+---+----+-------+-----+-----+-------+
+       |   |  |                            |     |             |
+       -----  ------------------------------     ---------------
+         \              |                               |
+           \            |                               |
+             \          |                               |
+               \        |    ----------------------------
+                 \      |   /
+                   \    |  /
+                     \  | /
+                  /proc/vmcore
+
 
         +---+
         |///| -> Regions (CPU, HPTE & Metadata) marked like this in the above
         +---+    figures are not always present. For example, OPAL platform
                  does not have CPU & HPTE regions while Metadata region is
                  not supported on pSeries currently.
 
+        +---+
+        |ELF| -> elfcorehdr, it is created in second kernel after crash.
+        +---+
+
+        Note: Memory from 0 to the boot memory size is used by second kernel
+
                    Fig. 2
 
 
@@ -353,26 +366,6 @@ TODO:
  - Need to come up with the better approach to find out more
    accurate boot memory size that is required for a kernel to
    boot successfully when booted with restricted memory.
- - The FADump implementation introduces a FADump crash info structure
-   in the scratch area before the ELF core header. The idea of introducing
-   this structure is to pass some important crash info data to the second
-   kernel which will help second kernel to populate ELF core header with
-   correct data before it gets exported through /proc/vmcore. The current
-   design implementation does not address a possibility of introducing
-   additional fields (in future) to this structure without affecting
-   compatibility. Need to come up with the better approach to address this.
-
-   The possible approaches are:
-
-	1. Introduce version field for version tracking, bump up the version
-	whenever a new field is added to the structure in future. The version
-	field can be used to find out what fields are valid for the current
-	version of the structure.
-	2. Reserve the area of predefined size (say PAGE_SIZE) for this
-	structure and have unused area as reserved (initialized to zero)
-	for future field additions.
-
-   The advantage of approach 1 over 2 is we don't need to reserve extra space.
 
 Author: Mahesh Salgaonkar <[email protected]>
 

MAINTAINERS

@@ -12470,7 +12470,6 @@ LINUX FOR POWERPC (32-BIT AND 64-BIT)
 M:	Michael Ellerman <[email protected]>
 R:	Nicholas Piggin <[email protected]>
 R:	Christophe Leroy <[email protected]>
-R:	Aneesh Kumar K.V <[email protected]>
 R:	Naveen N. Rao <[email protected]>
 L:	[email protected]
 S:	Supported
@@ -14893,7 +14892,7 @@ F:	drivers/phy/marvell/phy-pxa-usb.c
 
 MMU GATHER AND TLB INVALIDATION
 M:	Will Deacon <[email protected]>
-M:	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
+M:	"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
 M:	Andrew Morton <[email protected]>
 M:	Nick Piggin <[email protected]>
 M:	Peter Zijlstra <[email protected]>

arch/powerpc/include/asm/fadump-internal.h

@@ -42,13 +42,38 @@ static inline u64 fadump_str_to_u64(const char *str)
 
 #define FADUMP_CPU_UNKNOWN		(~((u32)0))
 
-#define FADUMP_CRASH_INFO_MAGIC		fadump_str_to_u64("FADMPINF")
+/*
+ * The introduction of new fields in the fadump crash info header has
+ * led to a change in the magic key from `FADMPINF` to `FADMPSIG` for
+ * identifying a kernel crash from an old kernel.
+ *
+ * To prevent the need for further changes to the magic number in the
+ * event of future modifications to the fadump crash info header, a
+ * version field has been introduced to track the fadump crash info
+ * header version.
+ *
+ * Consider a few points before adding new members to the fadump crash info
+ * header structure:
+ *
+ *  - Append new members; avoid adding them in between.
+ *  - Non-primitive members should have a size member as well.
+ *  - For every change in the fadump header, increment the
+ *    fadump header version. This helps the updated kernel decide how to
+ *    handle kernel dumps from older kernels.
+ */
+#define FADUMP_CRASH_INFO_MAGIC_OLD	fadump_str_to_u64("FADMPINF")
+#define FADUMP_CRASH_INFO_MAGIC		fadump_str_to_u64("FADMPSIG")
+#define FADUMP_HEADER_VERSION		1
 
 /* fadump crash info structure */
 struct fadump_crash_info_header {
 	u64		magic_number;
-	u64		elfcorehdr_addr;
+	u32		version;
 	u32		crashing_cpu;
+	u64		vmcoreinfo_raddr;
+	u64		vmcoreinfo_size;
+	u32		pt_regs_sz;
+	u32		cpu_mask_sz;
 	struct pt_regs	regs;
 	struct cpumask	cpu_mask;
 };
@@ -94,6 +119,8 @@ struct fw_dump {
 	u64		boot_mem_regs_cnt;
 
 	unsigned long	fadumphdr_addr;
+	u64		elfcorehdr_addr;
+	u64		elfcorehdr_size;
 	unsigned long	cpu_notes_buf_vaddr;
 	unsigned long	cpu_notes_buf_size;
 

arch/powerpc/include/asm/hvcall.h

@@ -524,7 +524,7 @@ long plpar_hcall_norets_notrace(unsigned long opcode, ...);
  * Used for all but the craziest of phyp interfaces (see plpar_hcall9)
  */
 #define PLPAR_HCALL_BUFSIZE 4
-long plpar_hcall(unsigned long opcode, unsigned long *retbuf, ...);
+long plpar_hcall(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL_BUFSIZE], ...);
 
 /**
  * plpar_hcall_raw: - Make a hypervisor call without calculating hcall stats
@@ -538,7 +538,7 @@ long plpar_hcall(unsigned long opcode, unsigned long *retbuf, ...);
  * plpar_hcall, but plpar_hcall_raw works in real mode and does not
  * calculate hypervisor call statistics.
  */
-long plpar_hcall_raw(unsigned long opcode, unsigned long *retbuf, ...);
+long plpar_hcall_raw(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL_BUFSIZE], ...);
 
 /**
  * plpar_hcall9: - Make a pseries hypervisor call with up to 9 return arguments
@@ -549,8 +549,8 @@ long plpar_hcall_raw(unsigned long opcode, unsigned long *retbuf, ...);
  * PLPAR_HCALL9_BUFSIZE to size the return argument buffer.
  */
 #define PLPAR_HCALL9_BUFSIZE 9
-long plpar_hcall9(unsigned long opcode, unsigned long *retbuf, ...);
-long plpar_hcall9_raw(unsigned long opcode, unsigned long *retbuf, ...);
+long plpar_hcall9(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL9_BUFSIZE], ...);
+long plpar_hcall9_raw(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL9_BUFSIZE], ...);
 
 /* pseries hcall tracing */
 extern struct static_key hcall_tracepoint_key;
@@ -570,7 +570,7 @@ struct hvcall_mpp_data {
 	unsigned long backing_mem;
 };
 
-int h_get_mpp(struct hvcall_mpp_data *);
+long h_get_mpp(struct hvcall_mpp_data *mpp_data);
 
 struct hvcall_mpp_x_data {
 	unsigned long coalesced_bytes;