History log of /linux-6.15/arch/powerpc/kernel/exceptions-64s.S (Results 1 – 25 of 476)
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Revision tags: v6.15, v6.15-rc7, v6.15-rc6, v6.15-rc5, v6.15-rc4, v6.15-rc3, v6.15-rc2, v6.15-rc1, v6.14, v6.14-rc7, v6.14-rc6, v6.14-rc5, v6.14-rc4, v6.14-rc3, v6.14-rc2, v6.14-rc1, v6.13, v6.13-rc7, v6.13-rc6, v6.13-rc5, v6.13-rc4
# 05bf59fb 18-Dec-2024 Michael Ellerman <[email protected]>

powerpc/cell: Remove support for IBM Cell Blades

IBM Cell Blades used the Cell processor and the "blade" server form
factor. They were sold as models QS20, QS21 & QS22 from roughly 2006 to
2012 [1].

powerpc/cell: Remove support for IBM Cell Blades

IBM Cell Blades used the Cell processor and the "blade" server form
factor. They were sold as models QS20, QS21 & QS22 from roughly 2006 to
2012 [1]. They were used in a few supercomputers (eg. Roadrunner) that
have since been dismantled, and were not that widely used otherwise.

Until recently I still had a working QS22, which meant I was able to
keep the platform support working, but unfortunately that machine has
now died.

I'm not aware of any users. If there is a user that wants to keep the
upstream support working, we can look at bringing some of the code back
as appropriate.

See previous discussion at [2].

Remove the top-level config symbol PPC_IBM_CELL_BLADE, and then
the dependent symbols PPC_CELL_NATIVE, PPC_CELL_COMMON, CBE_RAS,
PPC_IBM_CELL_RESETBUTTON, PPC_IBM_CELL_POWERBUTTON, CBE_THERM, and
AXON_MSI. Then remove the associated C files and headers, and trim
unused header content (some is shared with PS3).

Note that PPC_CELL_COMMON sounds like it would build code shared with
PS3, but it does not. It's a relic from when code was shared between the
Blade support and QPACE support.

Most of the primary authors already have CREDITS entries, with the
exception of Christian, so add one for him.

[1]: https://www.theregister.com/2011/06/28/ibm_kills_qs22_blade
[2]: https://lore.kernel.org/linuxppc-dev/[email protected]

Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Jeremy Kerr <[email protected]>
Acked-by: Segher Boessenkool <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Madhavan Srinivasan <[email protected]>
Link: https://patch.msgid.link/[email protected]

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Revision tags: v6.13-rc3, v6.13-rc2, v6.13-rc1, v6.12, v6.12-rc7, v6.12-rc6, v6.12-rc5, v6.12-rc4, v6.12-rc3, v6.12-rc2, v6.12-rc1, v6.11, v6.11-rc7, v6.11-rc6, v6.11-rc5
# 29dbb984 23-Aug-2024 Michael Ellerman <[email protected]>

powerpc/64s: Remove the "fast endian switch" syscall

The non-standard "fast endian switch" syscall was added in 2008[1],
but was never widely used. It was disabled by default in 2017[2], and
there's

powerpc/64s: Remove the "fast endian switch" syscall

The non-standard "fast endian switch" syscall was added in 2008[1],
but was never widely used. It was disabled by default in 2017[2], and
there's no evidence it's ever been used since.

Remove it entirely.

A normal endian switch syscall was added in 2015[3].

[1]: 745a14cc264b ("[POWERPC] Add fast little-endian switch system call")
[2]: 529d235a0e19 ("powerpc: Add a proper syscall for switching endianness")
[3]: 727f13616c45 ("powerpc: Disable the fast-endian switch syscall by default")

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

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Revision tags: v6.11-rc4, v6.11-rc3, v6.11-rc2, v6.11-rc1, v6.10, v6.10-rc7, v6.10-rc6, v6.10-rc5, v6.10-rc4, v6.10-rc3, v6.10-rc2, v6.10-rc1, v6.9, v6.9-rc7, v6.9-rc6, v6.9-rc5, v6.9-rc4, v6.9-rc3, v6.9-rc2, v6.9-rc1, v6.8, v6.8-rc7, v6.8-rc6, v6.8-rc5, v6.8-rc4, v6.8-rc3, v6.8-rc2, v6.8-rc1, v6.7, v6.7-rc8, v6.7-rc7, v6.7-rc6, v6.7-rc5, v6.7-rc4, v6.7-rc3, v6.7-rc2, v6.7-rc1, v6.6, v6.6-rc7, v6.6-rc6, v6.6-rc5, v6.6-rc4, v6.6-rc3, v6.6-rc2, v6.6-rc1, v6.5
# 17e02586 26-Aug-2023 Costa Shulyupin <[email protected]>

docs: move powerpc under arch

and fix all in-tree references.

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directo

docs: move powerpc under arch

and fix all in-tree references.

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.

Signed-off-by: Costa Shulyupin <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.5-rc7, v6.5-rc6, v6.5-rc5, v6.5-rc4, v6.5-rc3, v6.5-rc2, v6.5-rc1, v6.4, v6.4-rc7, v6.4-rc6, v6.4-rc5, v6.4-rc4, v6.4-rc3, v6.4-rc2, v6.4-rc1, v6.3, v6.3-rc7, v6.3-rc6
# 4e991e3c 08-Apr-2023 Nicholas Piggin <[email protected]>

powerpc: add CFUNC assembly label annotation

This macro is to be used in assembly where C functions are called.
pcrel addressing mode requires branches to functions with a
localentry value of 1 to h

powerpc: add CFUNC assembly label annotation

This macro is to be used in assembly where C functions are called.
pcrel addressing mode requires branches to functions with a
localentry value of 1 to have either a trailing nop or @notoc.
This macro permits the latter without changing callers.

Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Add dummy definitions to fix selftests build]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

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Revision tags: v6.3-rc5, v6.3-rc4, v6.3-rc3, v6.3-rc2, v6.3-rc1, v6.2, v6.2-rc8, v6.2-rc7, v6.2-rc6, v6.2-rc5, v6.2-rc4, v6.2-rc3, v6.2-rc2, v6.2-rc1, v6.1, v6.1-rc8
# 1df45d78 01-Dec-2022 Rohan McLure <[email protected]>

powerpc/64s: Zeroise gprs on interrupt routine entry on Book3S

Zeroise user state in gprs (assign to zero) to reduce the influence of user
registers on speculation within kernel syscall handlers. Cl

powerpc/64s: Zeroise gprs on interrupt routine entry on Book3S

Zeroise user state in gprs (assign to zero) to reduce the influence of user
registers on speculation within kernel syscall handlers. Clears occur
at the very beginning of the sc and scv 0 interrupt handlers, with
restores occurring following the execution of the syscall handler.

Zeroise GPRS r0, r2-r11, r14-r31, on entry into the kernel for all
other interrupt sources. The remaining gprs are overwritten by
entry macros to interrupt handlers, irrespective of whether or not a
given handler consumes these register values. If an interrupt does not
select the IMSR_R12 IOption, zeroise r12.

Prior to this commit, r14-r31 are restored on a per-interrupt basis at
exit, but now they are always restored on 64bit Book3S. Remove explicit
REST_NVGPRS invocations on 64-bit Book3S. 32-bit systems do not clear
user registers on interrupt, and continue to depend on the return value
of interrupt_exit_user_prepare to determine whether or not to restore
non-volatiles.

The mmap_bench benchmark in selftests should rapidly invoke pagefaults.
See ~0.8% performance regression with this mitigation, but this
indicates the worst-case performance due to heavier-weight interrupt
handlers. This mitigation is able to be enabled/disabled through
CONFIG_INTERRUPT_SANITIZE_REGISTERS.

Reviewed-by: Nicholas Piggin <[email protected]>
Signed-off-by: Rohan McLure <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 2487fd2e 01-Dec-2022 Rohan McLure <[email protected]>

powerpc/64s: IOption for MSR stored in r12

Interrupt handlers in asm/exceptions-64s.S contain a great deal of common
code produced by the GEN_COMMON macros. Currently, at the exit point of
the macro

powerpc/64s: IOption for MSR stored in r12

Interrupt handlers in asm/exceptions-64s.S contain a great deal of common
code produced by the GEN_COMMON macros. Currently, at the exit point of
the macro, r12 will contain the contents of the MSR. A future patch will
cause these macros to zeroise architected registers to avoid potential
speculation influence of user data.

Provide an IOption that signals that r12 must be retained, as the
interrupt handler assumes it to hold the contents of the MSR.

Reviewed-by: Nicholas Piggin <[email protected]>
Signed-off-by: Rohan McLure <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.1-rc7
# d2e8ff9f 27-Nov-2022 Nicholas Piggin <[email protected]>

powerpc: add a definition for the marker offset within the interrupt frame

Define a constant rather than open-code the offset for the
"regs" marker.

Signed-off-by: Nicholas Piggin <[email protected]

powerpc: add a definition for the marker offset within the interrupt frame

Define a constant rather than open-code the offset for the
"regs" marker.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# c03be0a3 27-Nov-2022 Nicholas Piggin <[email protected]>

powerpc: add definition for pt_regs offset within an interrupt frame

This is a common offset that currently uses the overloaded
STACK_FRAME_OVERHEAD constant. It's easier to read and more
flexible t

powerpc: add definition for pt_regs offset within an interrupt frame

This is a common offset that currently uses the overloaded
STACK_FRAME_OVERHEAD constant. It's easier to read and more
flexible to use a specific regs offset for this.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.1-rc6
# 29a011fc 14-Nov-2022 Sathvika Vasireddy <[email protected]>

powerpc: Fix objtool unannotated intra-function call warnings

Objtool throws unannotated intra-function call warnings in the following
assembly files:

arch/powerpc/kernel/vector.o: warning: objtool

powerpc: Fix objtool unannotated intra-function call warnings

Objtool throws unannotated intra-function call warnings in the following
assembly files:

arch/powerpc/kernel/vector.o: warning: objtool: .text+0x53c: unannotated intra-function call

arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0x60: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0x124: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0x5d4: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0x5dc: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0xcb8: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0xd0c: unannotated intra-function call
arch/powerpc/kvm/book3s_hv_rmhandlers.o: warning: objtool: .text+0x1030: unannotated intra-function call

arch/powerpc/kernel/head_64.o: warning: objtool: .text+0x358: unannotated intra-function call
arch/powerpc/kernel/head_64.o: warning: objtool: .text+0x728: unannotated intra-function call
arch/powerpc/kernel/head_64.o: warning: objtool: .text+0x4d94: unannotated intra-function call
arch/powerpc/kernel/head_64.o: warning: objtool: .text+0x4ec4: unannotated intra-function call

arch/powerpc/kvm/book3s_hv_interrupts.o: warning: objtool: .text+0x6c: unannotated intra-function call
arch/powerpc/kernel/misc_64.o: warning: objtool: .text+0x64: unannotated intra-function call

Objtool does not add STT_NOTYPE symbols with size 0 to the rbtree, which
is why find_call_destination() function is not able to find the
destination symbol for 'bl' instruction. For such symbols, objtool is
throwing unannotated intra-function call warnings in assembly files. Fix
these warnings by annotating those symbols with SYM_FUNC_START_LOCAL and
SYM_FUNC_END macros, inorder to set symbol type to STT_FUNC and symbol
size accordingly.

Tested-by: Naveen N. Rao <[email protected]>
Reviewed-by: Naveen N. Rao <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Sathvika Vasireddy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.1-rc5, v6.1-rc4, v6.1-rc3, v6.1-rc2, v6.1-rc1
# dc398a08 06-Oct-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: Perf NMI should not take normal exit path

NMI interrupts should exit with EXCEPTION_RESTORE_REGS not with
interrupt_return_srr, which is what the perf NMI handler currently do

powerpc/64s/interrupt: Perf NMI should not take normal exit path

NMI interrupts should exit with EXCEPTION_RESTORE_REGS not with
interrupt_return_srr, which is what the perf NMI handler currently does.
This breaks if a PMI hits after interrupt_exit_user_prepare_main() has
switched the context tracking to user mode, then the CT_WARN_ON() in
interrupt_exit_kernel_prepare() fires because it returns to kernel with
context set to user.

This could possibly be solved by soft-disabling PMIs in the exit path,
but that reduces our ability to profile that code. The warning could be
removed, but it's potentially useful.

All other NMIs and soft-NMIs return using EXCEPTION_RESTORE_REGS, so
this makes perf interrupts consistent with that and seems like the best
fix.

Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Squash in fixups from Nick]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# b2e82e49 04-Oct-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: Fix stack frame regs marker

The value of the stack frame regs marker that gets saved on the stack in
interrupt entry code does not match the regs marker value, which breaks
st

powerpc/64s/interrupt: Fix stack frame regs marker

The value of the stack frame regs marker that gets saved on the stack in
interrupt entry code does not match the regs marker value, which breaks
stack frame marker matching.

This stray instruction looks to have been introduced in a mismerge.

Fixes: bf75a3258a403 ("powerpc/64s/interrupt: move early boot ILE fixup into a macro")
Signed-off-by: Nicholas Piggin <[email protected]>
[mpe: Mismerge by yours truly -_-]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 8154850b 04-Oct-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: Change must-hard-mask interrupt check from BUG to WARN

This new assertion added is generally harmless and gets fixed up
naturally, but it does indicate a problem with MSR mani

powerpc/64s/interrupt: Change must-hard-mask interrupt check from BUG to WARN

This new assertion added is generally harmless and gets fixed up
naturally, but it does indicate a problem with MSR manipulation
somewhere.

Fixes: c39fb71a54f0 ("powerpc/64s/interrupt: masked handler debug check for previous hard disable")
Reported-by: Sachin Sant <[email protected]>
Signed-off-by: Nicholas Piggin <[email protected]>
Tested-by: Sachin Sant <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.0
# 0c360996 28-Sep-2022 Michael Ellerman <[email protected]>

powerpc/64s: Remove lost/old comment

The bulk of this was moved/reworded in:
57f266497d81 ("powerpc: Use gas sections for arranging exception vectors")

And now appears around line 700 in arch/pow

powerpc/64s: Remove lost/old comment

The bulk of this was moved/reworded in:
57f266497d81 ("powerpc: Use gas sections for arranging exception vectors")

And now appears around line 700 in arch/powerpc/kernel/exceptions-64s.S.

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 57a8e4b2 28-Sep-2022 Michael Ellerman <[email protected]>

powerpc/64s: Remove old STAB comment

This used to be about the 0x4300 handler, but that was moved in commit
da2bc4644c75 ("powerpc/64s: Add new exception vector macros").

Note that "STAB" here refe

powerpc/64s: Remove old STAB comment

This used to be about the 0x4300 handler, but that was moved in commit
da2bc4644c75 ("powerpc/64s: Add new exception vector macros").

Note that "STAB" here refers to "Segment Table" not the debug format.

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# e1100cee 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: halt early boot interrupts if paca is not set up

Ensure r13 is zero from very early in boot until it gets set to the
boot paca pointer. This allows early program and mce handl

powerpc/64s/interrupt: halt early boot interrupts if paca is not set up

Ensure r13 is zero from very early in boot until it gets set to the
boot paca pointer. This allows early program and mce handlers to halt
if there is no valid paca, rather than potentially run off into the
weeds. This preserves register and memory contents for low level
debugging tools.

Nothing could be printed to console at this point in any case because
even udbg is only set up after the boot paca is set, so this shouldn't
be missed.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 2f5182cf 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64s: early boot machine check handler

Use the early boot interrupt fixup in the machine check handler to allow
the machine check handler to run before interrupt endian is set up.
Branch to a

powerpc/64s: early boot machine check handler

Use the early boot interrupt fixup in the machine check handler to allow
the machine check handler to run before interrupt endian is set up.
Branch to an early boot handler that just does a basic crash, which
allows it to run before ppc_md is set up. MSR[ME] is enabled on the boot
CPU earlier, and the machine check stack is temporarily set to the
middle of the init task stack.

This allows machine checks (e.g., due to invalid data access in real
mode) to print something useful earlier in boot (as soon as udbg is set
up, if CONFIG_PPC_EARLY_DEBUG=y).

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# bf75a325 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: move early boot ILE fixup into a macro

In preparation for using this sequence in machine check interrupt, move
it into a macro, with a small change to make it position indepen

powerpc/64s/interrupt: move early boot ILE fixup into a macro

In preparation for using this sequence in machine check interrupt, move
it into a macro, with a small change to make it position independent.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 8e93fb33 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64: provide a helper macro to load r2 with the kernel TOC

A later change stops the kernel using r2 and loads it with a poison
value. Provide a PACATOC loading abstraction which can hide thi

powerpc/64: provide a helper macro to load r2 with the kernel TOC

A later change stops the kernel using r2 and loads it with a poison
value. Provide a PACATOC loading abstraction which can hide this
detail.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# 17773afd 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64: use 32-bit immediate for STACK_FRAME_REGS_MARKER

Using a 32-bit constant for this marker allows it to be loaded with
two ALU instructions, like 32-bit. This avoids a TOC entry and a
TOC

powerpc/64: use 32-bit immediate for STACK_FRAME_REGS_MARKER

Using a 32-bit constant for this marker allows it to be loaded with
two ALU instructions, like 32-bit. This avoids a TOC entry and a
TOC load that depends on the r2 value that has just been loaded from
the PACA.

This changes the value for 32-bit as well, so both have the same
value in the low 4 bytes and 64-bit has 0 in the top bytes.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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# c39fb71a 26-Sep-2022 Nicholas Piggin <[email protected]>

powerpc/64s/interrupt: masked handler debug check for previous hard disable

Prior changes eliminated cases of masked PACA_IRQ_MUST_HARD_MASK
interrupts that re-fire due to MSR[EE] being enabled whil

powerpc/64s/interrupt: masked handler debug check for previous hard disable

Prior changes eliminated cases of masked PACA_IRQ_MUST_HARD_MASK
interrupts that re-fire due to MSR[EE] being enabled while they are
pending. Add a debug check in the masked interrupt handler to catch
if this occurs.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.0-rc7
# 620f5c59 21-Sep-2022 Rohan McLure <[email protected]>

powerpc/64s: Fix comment on interrupt handler prologue

Interrupt handlers on 64s systems will often need to save register state
from the interrupted process to make space for loading special purpose

powerpc/64s: Fix comment on interrupt handler prologue

Interrupt handlers on 64s systems will often need to save register state
from the interrupted process to make space for loading special purpose
registers or for internal state.

Fix a comment documenting a common code path macro in the beginning of
interrupt handlers where r10 is saved to the PACA to afford space for
the value of the CFAR. Comment is currently written as if r10-r12 are
saved to PACA, but in fact only r10 is saved, with r11-r12 saved much
later. The distance in code between these saves has grown over the many
revisions of this macro. Fix this by signalling with a comment where
r11-r12 are saved to the PACA.

Signed-off-by: Rohan McLure <[email protected]>
Reported-by: Nicholas Piggin <[email protected]>
Reviewed-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v6.0-rc6, v6.0-rc5, v6.0-rc4, v6.0-rc3, v6.0-rc2, v6.0-rc1, v5.19, v5.19-rc8
# 2b461880 18-Jul-2022 Michael Ellerman <[email protected]>

powerpc: Fix all occurences of duplicate words

Since commit 87c78b612f4f ("powerpc: Fix all occurences of "the the"")
fixed "the the", there's now a steady stream of patches fixing other
duplicate w

powerpc: Fix all occurences of duplicate words

Since commit 87c78b612f4f ("powerpc: Fix all occurences of "the the"")
fixed "the the", there's now a steady stream of patches fixing other
duplicate words.

Just fix them all at once, to save the overhead of dealing with
individual patches for each case.

This leaves a few cases of "that that", which in some contexts is
correct.

Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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Revision tags: v5.19-rc7, v5.19-rc6, v5.19-rc5, v5.19-rc4, v5.19-rc3, v5.19-rc2, v5.19-rc1, v5.18, v5.18-rc7, v5.18-rc6, v5.18-rc5, v5.18-rc4, v5.18-rc3, v5.18-rc2, v5.18-rc1, v5.17, v5.17-rc8, v5.17-rc7, v5.17-rc6
# b5149e22 22-Feb-2022 Nicholas Piggin <[email protected]>

KVM: PPC: Book3S PR: Disable SCV when AIL could be disabled

PR KVM does not support running with AIL enabled, and SCV does is not
supported with AIL disabled. Fix this by ensuring the SCV facility i

KVM: PPC: Book3S PR: Disable SCV when AIL could be disabled

PR KVM does not support running with AIL enabled, and SCV does is not
supported with AIL disabled. Fix this by ensuring the SCV facility is
disabled with FSCR while a CPU could be running with AIL=0.

The PowerNV host supports disabling AIL on a per-CPU basis, so SCV just
needs to be disabled when a vCPU is being run.

The pSeries machine can only switch AIL on a system-wide basis, so it
must disable SCV support at boot if the configuration can potentially
run a PR KVM guest.

Also ensure a the FSCR[SCV] bit can not be enabled when emulating
mtFSCR for the guest.

SCV is not emulated for the PR guest at the moment, this just fixes the
host crashes.

Alternatives considered and rejected:
- SCV support can not be disabled by PR KVM after boot, because it is
advertised to userspace with HWCAP.
- AIL can not be disabled on a per-CPU basis. At least when running on
pseries it is a per-LPAR setting.
- Support for real-mode SCV vectors will not be added because they are
at 0x17000 so making such a large fixed head space causes immediate
value limits to be exceeded, requiring a lot rework and more code.
- Disabling SCV for any PR KVM possible kernel will cause a slowdown
when not using PR KVM.
- A boot time option to disable SCV to use PR KVM is user-hostile.
- System call instruction emulation for SCV facility unavailable
instructions is too complex and old emulation code was subtly broken
and removed.

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Reviewed-by: Fabiano Rosas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...


Revision tags: v5.17-rc5, v5.17-rc4, v5.17-rc3, v5.17-rc2, v5.17-rc1, v5.16, v5.16-rc8, v5.16-rc7
# d72c4a36 21-Dec-2021 Daniel Axtens <[email protected]>

powerpc/64/asm: Do not reassign labels

The LLVM integrated assembler really does not like us reassigning things
to the same label:

<instantiation>:7:9: error: invalid reassignment of non-absolute v

powerpc/64/asm: Do not reassign labels

The LLVM integrated assembler really does not like us reassigning things
to the same label:

<instantiation>:7:9: error: invalid reassignment of non-absolute variable 'fs_label'

This happens across a bunch of platforms:
https://github.com/ClangBuiltLinux/linux/issues/1043
https://github.com/ClangBuiltLinux/linux/issues/1008
https://github.com/ClangBuiltLinux/linux/issues/920
https://github.com/ClangBuiltLinux/linux/issues/1050

There is no hope of getting this fixed in LLVM (see
https://github.com/ClangBuiltLinux/linux/issues/1043#issuecomment-641571200
and https://bugs.llvm.org/show_bug.cgi?id=47798#c1 )
so if we want to build with LLVM_IAS, we need to hack
around it ourselves.

For us the big problem comes from this:

\#define USE_FIXED_SECTION(sname) \
fs_label = start_##sname; \
fs_start = sname##_start; \
use_ftsec sname;

\#define USE_TEXT_SECTION()
fs_label = start_text; \
fs_start = text_start; \
.text

and in particular fs_label.

This works around it by not setting those 'variables' and requiring
that users of the variables instead track for themselves what section
they are in. This isn't amazing, by any stretch, but it gets us further
in the compilation.

Note that even though users have to keep track of the section, using
a wrong one produces an error with both binutils and llvm which prevents
from using wrong section at the compile time:

llvm error example:

AS arch/powerpc/kernel/head_64.o
<unknown>:0: error: Cannot represent a difference across sections
make[3]: *** [/home/aik/p/kernels-llvm/llvm/scripts/Makefile.build:388: arch/powerpc/kernel/head_64.o] Error 1

binutils error example:

/home/aik/p/kernels-llvm/llvm/arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
/home/aik/p/kernels-llvm/llvm/arch/powerpc/kernel/exceptions-64s.S:1974: Error: can't resolve `system_call_common' {.text section} - `start_r
eal_vectors' {.head.text.real_vectors section}
make[3]: *** [/home/aik/p/kernels-llvm/llvm/scripts/Makefile.build:388: arch/powerpc/kernel/head_64.o] Error 1

Signed-off-by: Daniel Axtens <[email protected]>
Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...


# fd983957 21-Dec-2021 Alexey Kardashevskiy <[email protected]>

powerpc/64/asm: Inline BRANCH_TO_C000

It is used just once and does not really help with readability, remove it.

Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman

powerpc/64/asm: Inline BRANCH_TO_C000

It is used just once and does not really help with readability, remove it.

Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...


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