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b57aeab811
Watchpoint match range is always doubleword(8 bytes) aligned on
powerpc. If the given range is crossing doubleword boundary, we need
to increase the length such that next doubleword also get
covered. Ex,
address len = 6 bytes
|=========.
|------------v--|------v--------|
| | | | | | | | | | | | | | | | |
|---------------|---------------|
<---8 bytes--->
In such case, current code configures hw as:
start_addr = address & ~HW_BREAKPOINT_ALIGN
len = 8 bytes
And thus read/write in last 4 bytes of the given range is ignored.
Fix this by including next doubleword in the length.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191017093204.7511-3-ravi.bangoria@linux.ibm.com
102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* DAWR infrastructure
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*
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* Copyright 2019, Michael Neuling, IBM Corporation.
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*/
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#include <linux/types.h>
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#include <linux/export.h>
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#include <linux/fs.h>
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#include <linux/debugfs.h>
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#include <asm/debugfs.h>
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#include <asm/machdep.h>
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#include <asm/hvcall.h>
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bool dawr_force_enable;
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EXPORT_SYMBOL_GPL(dawr_force_enable);
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int set_dawr(struct arch_hw_breakpoint *brk)
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{
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unsigned long dawr, dawrx, mrd;
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dawr = brk->address;
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dawrx = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE))
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<< (63 - 58);
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dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) << (63 - 59);
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dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) >> 3;
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/*
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* DAWR length is stored in field MDR bits 48:53. Matches range in
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* doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
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* 0b111111=64DW.
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* brk->hw_len is in bytes.
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* This aligns up to double word size, shifts and does the bias.
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*/
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mrd = ((brk->hw_len + 7) >> 3) - 1;
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dawrx |= (mrd & 0x3f) << (63 - 53);
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if (ppc_md.set_dawr)
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return ppc_md.set_dawr(dawr, dawrx);
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mtspr(SPRN_DAWR, dawr);
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mtspr(SPRN_DAWRX, dawrx);
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return 0;
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}
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static void set_dawr_cb(void *info)
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{
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set_dawr(info);
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}
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static ssize_t dawr_write_file_bool(struct file *file,
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const char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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struct arch_hw_breakpoint null_brk = {0};
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size_t rc;
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/* Send error to user if they hypervisor won't allow us to write DAWR */
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if (!dawr_force_enable &&
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firmware_has_feature(FW_FEATURE_LPAR) &&
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set_dawr(&null_brk) != H_SUCCESS)
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return -ENODEV;
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rc = debugfs_write_file_bool(file, user_buf, count, ppos);
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if (rc)
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return rc;
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/* If we are clearing, make sure all CPUs have the DAWR cleared */
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if (!dawr_force_enable)
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smp_call_function(set_dawr_cb, &null_brk, 0);
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return rc;
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}
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static const struct file_operations dawr_enable_fops = {
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.read = debugfs_read_file_bool,
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.write = dawr_write_file_bool,
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.open = simple_open,
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.llseek = default_llseek,
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};
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static int __init dawr_force_setup(void)
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{
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if (cpu_has_feature(CPU_FTR_DAWR)) {
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/* Don't setup sysfs file for user control on P8 */
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dawr_force_enable = true;
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return 0;
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}
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if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {
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/* Turn DAWR off by default, but allow admin to turn it on */
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debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,
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powerpc_debugfs_root,
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&dawr_force_enable,
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&dawr_enable_fops);
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}
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return 0;
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}
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arch_initcall(dawr_force_setup);
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