diff options
author | Michael Neuling <mikey@neuling.org> | 2019-06-04 13:00:37 +1000 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-07-03 15:19:35 +1000 |
commit | a278e7ea608bea5fe6df9b6ae91fa134655c5d2c (patch) | |
tree | 5eeb4faa4d6b050d034841d488b9e916429c6af5 /arch/powerpc/kernel/dawr.c | |
parent | 548c54acba5bd1388d50727a9a126a42d0cd4ad0 (diff) | |
download | linux-a278e7ea608bea5fe6df9b6ae91fa134655c5d2c.tar.bz2 |
powerpc: Fix compile issue with force DAWR
If you compile with KVM but without CONFIG_HAVE_HW_BREAKPOINT you fail
at linking with:
arch/powerpc/kvm/book3s_hv_rmhandlers.o:(.text+0x708): undefined reference to `dawr_force_enable'
This was caused by commit c1fe190c0672 ("powerpc: Add force enable of
DAWR on P9 option").
This moves a bunch of code around to fix this. It moves a lot of the
DAWR code in a new file and creates a new CONFIG_PPC_DAWR to enable
compiling it.
Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option")
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Minor formatting in set_dawr()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/dawr.c')
-rw-r--r-- | arch/powerpc/kernel/dawr.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c new file mode 100644 index 000000000000..5f66b95b6858 --- /dev/null +++ b/arch/powerpc/kernel/dawr.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * DAWR infrastructure + * + * Copyright 2019, Michael Neuling, IBM Corporation. + */ + +#include <linux/types.h> +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <asm/debugfs.h> +#include <asm/machdep.h> +#include <asm/hvcall.h> + +bool dawr_force_enable; +EXPORT_SYMBOL_GPL(dawr_force_enable); + +int set_dawr(struct arch_hw_breakpoint *brk) +{ + unsigned long dawr, dawrx, mrd; + + dawr = brk->address; + + dawrx = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)) + << (63 - 58); + dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) << (63 - 59); + dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) >> 3; + /* + * DAWR length is stored in field MDR bits 48:53. Matches range in + * doublewords (64 bits) baised by -1 eg. 0b000000=1DW and + * 0b111111=64DW. + * brk->len is in bytes. + * This aligns up to double word size, shifts and does the bias. + */ + mrd = ((brk->len + 7) >> 3) - 1; + dawrx |= (mrd & 0x3f) << (63 - 53); + + if (ppc_md.set_dawr) + return ppc_md.set_dawr(dawr, dawrx); + + mtspr(SPRN_DAWR, dawr); + mtspr(SPRN_DAWRX, dawrx); + + return 0; +} + +static void set_dawr_cb(void *info) +{ + set_dawr(info); +} + +static ssize_t dawr_write_file_bool(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct arch_hw_breakpoint null_brk = {0, 0, 0}; + size_t rc; + + /* Send error to user if they hypervisor won't allow us to write DAWR */ + if (!dawr_force_enable && + firmware_has_feature(FW_FEATURE_LPAR) && + set_dawr(&null_brk) != H_SUCCESS) + return -ENODEV; + + rc = debugfs_write_file_bool(file, user_buf, count, ppos); + if (rc) + return rc; + + /* If we are clearing, make sure all CPUs have the DAWR cleared */ + if (!dawr_force_enable) + smp_call_function(set_dawr_cb, &null_brk, 0); + + return rc; +} + +static const struct file_operations dawr_enable_fops = { + .read = debugfs_read_file_bool, + .write = dawr_write_file_bool, + .open = simple_open, + .llseek = default_llseek, +}; + +static int __init dawr_force_setup(void) +{ + if (cpu_has_feature(CPU_FTR_DAWR)) { + /* Don't setup sysfs file for user control on P8 */ + dawr_force_enable = true; + return 0; + } + + if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) { + /* Turn DAWR off by default, but allow admin to turn it on */ + debugfs_create_file_unsafe("dawr_enable_dangerous", 0600, + powerpc_debugfs_root, + &dawr_force_enable, + &dawr_enable_fops); + } + return 0; +} +arch_initcall(dawr_force_setup); |