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03f3e54abd
2nd DAWR can be set/unset using H_SET_MODE hcall with resource value 5. Enable powervm guest support with that. This has no effect on kvm guest because kvm will return error if guest does hcall with resource value 5. 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/20200723090813.303838-9-ravi.bangoria@linux.ibm.com
110 lines
2.6 KiB
C
110 lines
2.6 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(int nr, 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(nr, dawr, dawrx);
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if (nr == 0) {
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mtspr(SPRN_DAWR0, dawr);
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mtspr(SPRN_DAWRX0, dawrx);
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} else {
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mtspr(SPRN_DAWR1, dawr);
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mtspr(SPRN_DAWRX1, dawrx);
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}
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return 0;
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}
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static void disable_dawrs_cb(void *info)
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{
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struct arch_hw_breakpoint null_brk = {0};
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int i;
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for (i = 0; i < nr_wp_slots(); i++)
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set_dawr(i, &null_brk);
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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(0, &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(disable_dawrs_cb, NULL, 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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