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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /lib/crypto/mpi/mpi-div.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
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Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'lib/crypto/mpi/mpi-div.c')
-rw-r--r--lib/crypto/mpi/mpi-div.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/lib/crypto/mpi/mpi-div.c b/lib/crypto/mpi/mpi-div.c
new file mode 100644
index 000000000..6e5044e72
--- /dev/null
+++ b/lib/crypto/mpi/mpi-div.c
@@ -0,0 +1,230 @@
+/* mpi-div.c - MPI functions
+ * Copyright (C) 1994, 1996, 1998, 2001, 2002,
+ * 2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Note: This code is heavily based on the GNU MP Library.
+ * Actually it's the same code with only minor changes in the
+ * way the data is stored; this is to support the abstraction
+ * of an optional secure memory allocation which may be used
+ * to avoid revealing of sensitive data due to paging etc.
+ */
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den);
+
+int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
+{
+ int divisor_sign = divisor->sign;
+ MPI temp_divisor = NULL;
+ int err;
+
+ /* We need the original value of the divisor after the remainder has been
+ * preliminary calculated. We have to copy it to temporary space if it's
+ * the same variable as REM.
+ */
+ if (rem == divisor) {
+ temp_divisor = mpi_copy(divisor);
+ if (!temp_divisor)
+ return -ENOMEM;
+ divisor = temp_divisor;
+ }
+
+ err = mpi_tdiv_r(rem, dividend, divisor);
+ if (err)
+ goto free_temp_divisor;
+
+ if (((divisor_sign?1:0) ^ (dividend->sign?1:0)) && rem->nlimbs)
+ err = mpi_add(rem, rem, divisor);
+
+free_temp_divisor:
+ mpi_free(temp_divisor);
+
+ return err;
+}
+
+/* If den == quot, den needs temporary storage.
+ * If den == rem, den needs temporary storage.
+ * If num == quot, num needs temporary storage.
+ * If den has temporary storage, it can be normalized while being copied,
+ * i.e no extra storage should be allocated.
+ */
+
+int mpi_tdiv_r(MPI rem, MPI num, MPI den)
+{
+ return mpi_tdiv_qr(NULL, rem, num, den);
+}
+
+int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
+{
+ mpi_ptr_t np, dp;
+ mpi_ptr_t qp, rp;
+ mpi_size_t nsize = num->nlimbs;
+ mpi_size_t dsize = den->nlimbs;
+ mpi_size_t qsize, rsize;
+ mpi_size_t sign_remainder = num->sign;
+ mpi_size_t sign_quotient = num->sign ^ den->sign;
+ unsigned int normalization_steps;
+ mpi_limb_t q_limb;
+ mpi_ptr_t marker[5];
+ int markidx = 0;
+ int err;
+
+ /* Ensure space is enough for quotient and remainder.
+ * We need space for an extra limb in the remainder, because it's
+ * up-shifted (normalized) below.
+ */
+ rsize = nsize + 1;
+ err = mpi_resize(rem, rsize);
+ if (err)
+ return err;
+
+ qsize = rsize - dsize; /* qsize cannot be bigger than this. */
+ if (qsize <= 0) {
+ if (num != rem) {
+ rem->nlimbs = num->nlimbs;
+ rem->sign = num->sign;
+ MPN_COPY(rem->d, num->d, nsize);
+ }
+ if (quot) {
+ /* This needs to follow the assignment to rem, in case the
+ * numerator and quotient are the same.
+ */
+ quot->nlimbs = 0;
+ quot->sign = 0;
+ }
+ return 0;
+ }
+
+ if (quot) {
+ err = mpi_resize(quot, qsize);
+ if (err)
+ return err;
+ }
+
+ /* Read pointers here, when reallocation is finished. */
+ np = num->d;
+ dp = den->d;
+ rp = rem->d;
+
+ /* Optimize division by a single-limb divisor. */
+ if (dsize == 1) {
+ mpi_limb_t rlimb;
+ if (quot) {
+ qp = quot->d;
+ rlimb = mpihelp_divmod_1(qp, np, nsize, dp[0]);
+ qsize -= qp[qsize - 1] == 0;
+ quot->nlimbs = qsize;
+ quot->sign = sign_quotient;
+ } else
+ rlimb = mpihelp_mod_1(np, nsize, dp[0]);
+ rp[0] = rlimb;
+ rsize = rlimb != 0?1:0;
+ rem->nlimbs = rsize;
+ rem->sign = sign_remainder;
+ return 0;
+ }
+
+ err = -ENOMEM;
+ if (quot) {
+ qp = quot->d;
+ /* Make sure QP and NP point to different objects. Otherwise the
+ * numerator would be gradually overwritten by the quotient limbs.
+ */
+ if (qp == np) { /* Copy NP object to temporary space. */
+ np = marker[markidx++] = mpi_alloc_limb_space(nsize);
+ if (!np)
+ goto out_free_marker;
+ MPN_COPY(np, qp, nsize);
+ }
+ } else /* Put quotient at top of remainder. */
+ qp = rp + dsize;
+
+ normalization_steps = count_leading_zeros(dp[dsize - 1]);
+
+ /* Normalize the denominator, i.e. make its most significant bit set by
+ * shifting it NORMALIZATION_STEPS bits to the left. Also shift the
+ * numerator the same number of steps (to keep the quotient the same!).
+ */
+ if (normalization_steps) {
+ mpi_ptr_t tp;
+ mpi_limb_t nlimb;
+
+ /* Shift up the denominator setting the most significant bit of
+ * the most significant word. Use temporary storage not to clobber
+ * the original contents of the denominator.
+ */
+ tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
+ if (!tp)
+ goto out_free_marker;
+ mpihelp_lshift(tp, dp, dsize, normalization_steps);
+ dp = tp;
+
+ /* Shift up the numerator, possibly introducing a new most
+ * significant word. Move the shifted numerator in the remainder
+ * meanwhile.
+ */
+ nlimb = mpihelp_lshift(rp, np, nsize, normalization_steps);
+ if (nlimb) {
+ rp[nsize] = nlimb;
+ rsize = nsize + 1;
+ } else
+ rsize = nsize;
+ } else {
+ /* The denominator is already normalized, as required. Copy it to
+ * temporary space if it overlaps with the quotient or remainder.
+ */
+ if (dp == rp || (quot && (dp == qp))) {
+ mpi_ptr_t tp;
+
+ tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
+ if (!tp)
+ goto out_free_marker;
+ MPN_COPY(tp, dp, dsize);
+ dp = tp;
+ }
+
+ /* Move the numerator to the remainder. */
+ if (rp != np)
+ MPN_COPY(rp, np, nsize);
+
+ rsize = nsize;
+ }
+
+ q_limb = mpihelp_divrem(qp, 0, rp, rsize, dp, dsize);
+
+ if (quot) {
+ qsize = rsize - dsize;
+ if (q_limb) {
+ qp[qsize] = q_limb;
+ qsize += 1;
+ }
+
+ quot->nlimbs = qsize;
+ quot->sign = sign_quotient;
+ }
+
+ rsize = dsize;
+ MPN_NORMALIZE(rp, rsize);
+
+ if (normalization_steps && rsize) {
+ mpihelp_rshift(rp, rp, rsize, normalization_steps);
+ rsize -= rp[rsize - 1] == 0?1:0;
+ }
+
+ rem->nlimbs = rsize;
+ rem->sign = sign_remainder;
+
+ err = 0;
+
+out_free_marker:
+ while (markidx) {
+ markidx--;
+ mpi_free_limb_space(marker[markidx]);
+ }
+
+ return err;
+}