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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/powerpc/kernel/dawr.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/kernel/dawr.c')
-rw-r--r-- | arch/powerpc/kernel/dawr.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c new file mode 100644 index 0000000000..909a05cd28 --- /dev/null +++ b/arch/powerpc/kernel/dawr.c @@ -0,0 +1,110 @@ +// 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/machdep.h> +#include <asm/hvcall.h> +#include <asm/firmware.h> + +bool dawr_force_enable; +EXPORT_SYMBOL_GPL(dawr_force_enable); + +int set_dawr(int nr, 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) biased by -1 eg. 0b000000=1DW and + * 0b111111=64DW. + * brk->hw_len is in bytes. + * This aligns up to double word size, shifts and does the bias. + */ + mrd = ((brk->hw_len + 7) >> 3) - 1; + dawrx |= (mrd & 0x3f) << (63 - 53); + + if (ppc_md.set_dawr) + return ppc_md.set_dawr(nr, dawr, dawrx); + + if (nr == 0) { + mtspr(SPRN_DAWR0, dawr); + mtspr(SPRN_DAWRX0, dawrx); + } else { + mtspr(SPRN_DAWR1, dawr); + mtspr(SPRN_DAWRX1, dawrx); + } + + return 0; +} + +static void disable_dawrs_cb(void *info) +{ + struct arch_hw_breakpoint null_brk = {0}; + int i; + + for (i = 0; i < nr_wp_slots(); i++) + set_dawr(i, &null_brk); +} + +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}; + 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(0, &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(disable_dawrs_cb, NULL, 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, + arch_debugfs_dir, + &dawr_force_enable, + &dawr_enable_fops); + } + return 0; +} +arch_initcall(dawr_force_setup); |